WO2000071051A1

WO2000071051A1 - Method and apparatus for extracting oocytes from ovaries

Info

Publication number: WO2000071051A1
Application number: PCT/AU2000/000496
Authority: WO
Inventors: Glenn Thomas Lyons; Andrew James Harford; Peter James Coleman
Original assignee: Genetics Australia Co-Operative Limited
Priority date: 1999-05-24
Filing date: 2000-05-24
Publication date: 2000-11-30
Also published as: AUPQ055899A0; NZ515510A

Abstract

A method and apparatus of extracting oocytes from ovaries. The apparatus includes an enclosure (11) for receiving a plurality of ovaries (27) and a plurality of probes (14) for repeatedly piercing the walls of the ovaries (27). The probes (14) are drivable by suitable drive means in reciprocating motion in the enclosure (11) and whereby repeated piercing of the ovary walls creates a plurality of openings in those walls through which oocytes within the ovaries (27) can be released into the enclosure (11) for collection.

Description

METHOD AND APPARATUS FOR EXTRACTING OOCYTES FROM OVARIES

The present invention relates to a method and apparatus for treating ovaries that have been ovariectomised, to extract oocytes (ova) therefrom. The invention is particularly useful for treating relatively large ovaries, such as bovine ovaries, although it is envisaged to also be applicable for the treatment of smaller ovaries. However, the invention will be described in relation to its use in the treatment of bovine ovaries.

The extraction of oocytes from ovaries is a necessary requirement for in vitro fertilisation breeding programmes, such as are now undertaken frequently by commercial graziers. Ovaries are removed from stock such as cattle or sheep, and are used in breeding programmes to improve stock quality. However, to date, the methods utilised for the extraction of oocytes from bovine ovaries have been labour intensive and slow. One known method for extracting oocytes from bovine ovaries involves aspiration of the ovary using a needle through which the oocyte is extracted and a vacuum pump or syringe to generate the vacuum necessary to remove the oocyte through the needle. Another method involves slicing the ovary open and removing the contents into a Petrie dish filled with a suitable collection solution. Both of these methods suffer the drawbacks discussed above and therefore they are therefore largely unsuitable for commercial oocyte extraction. Additionally, the methods presently employed tend to damage the oocytes, thus reducing the number of viable oocytes obtained and available for the breeding programmes. It is an object of the present invention to provide a method and apparatus for the extraction of oocytes from ovaries which overcomes or at least alleviates one or more of the aforementioned disadvantages.

The present invention provides a method of extracting oocytes from ovaries, said method including placing a plurality of ovaries in an enclosure and repeatedly piercing the walls of the ovaries with a plurality of probes which move in a reciprocating motion in the enclosure, the repeated piercing of the ovary walls creating a plurality of openings through which oocytes within the ovaries can pass into the enclosure for collection. The present invention further provides apparatus for extracting oocytes from ovaries, said apparatus including an enclosure for receiving a plurality of ovaries and a plurality of probes for repeatedly piercing the walls of the ovaries which are drivable by drive means in a reciprocating motion in the enclosure, repeated piercing of the ovary walls creating a plurality of openings through which oocytes within the ovaries can pass into the enclosure for collection.

The enclosure of the apparatus described above preferably has sufficient capacity to receive at least approximately 10 ovaries for treatment, although an even larger capacity is possible and will be preferred for future expanded commercial operations, in which the capacity preferably is approximately 50 ovaries. The capacity of the enclosure can vary depending on the type, and therefore the size of the ovaries being treated, so that a smaller enclosure is acceptable for ovaries of a generally smaller size.

The enclosure can have any suitable shape, but preferably it is square or circular. Preferably, the enclosure is of such a cross-sectional area that the ovaries can be spread over the base surface of the enclosure and are not stacked on top of each other.

In a preferred arrangement, the enclosure is divided vertically into two separate compartments, with a partition separating the compartments. In this arrangement, the upper compartment is provided to receive a plurality of ovaries for treatment while the lower compartment forms a collection sink for oocytes which have been extracted from the ovaries. In this arrangement, it is preferable that a liquid medium at least fills the lower compartment and preferably also at least partially fills the upper compartment. The liquid medium facilitates movement of the extracted oocytes from the upper compartment to the lower compartment in a manner which minimises the damage caused to each oocyte. In the liquid medium, the extracted oocytes fall under the effect of gravity into the lower compartment, where they can be subsequently collected, either continuously during operation of the apparatus, or when operation of the apparatus for the group of ovaries undergoing treatment has been finished.

In the above arrangement, the partition is required to enable the extracted oocytes to pass from the upper compartment to the lower compartment. Thus, the partition is required to be permeable and any suitable partition having that characteristic can be employed. In one preferred arrangement the partition can comprise a mesh screen, which has openings sufficiently small to prevent passage of the ovaries between the upper and lower compartments, but which facilitates passage of the extracted oocytes. A mesh screen of this type can be made of suitable plastic which has no toxic or reactive effect on the extracted oocytes, or it can be made from other materials, such as stainless steel.

The piercing probes employed for piercing the ovary walls are preferably elongate, such as needle-like, and have one end fixed to a mounting plate and the other piercing end sharpened, or in the form of a point. The construction of the piercing end is required to be such that the probes can pierce the wall of the ovary and, upon removal of the probe from the ovary, preferably leave an opening of sufficient size to enable oocytes within the ovary to be released through the opening. Alternatively, the opening created by a single probe puncture may not create an opening of sufficient size for the release of oocytes therethrough, and it may be that several punctures to the same part of the ovary wall are required for an opening of sufficient size to be created. The reciprocating nature of the probes facilitates repeated punctures to be made of the ovary wall and thus for suitably sized openings to be created for the release of oocytes.

As previously mentioned, the piercing probes are preferably connected at one end to a mounting plate. The probes may be connected to the mounting plate in any suitable manner, such as by threaded connection into threaded openings in the mounting plate, or by a suitable adhesive connection. Various other connecting arrangements could equally be employed. The probes are preferably fixedly mounted to the mounting plate, so that reciprocating motion applied by the drive means to the mounting plate results in reciprocating motion of the probes. The stroke of the probes is preferably such as to pierce through one side of the ovary wall and out the opposite side. The drive means can take any suitable form and for example could include a cam shaft with a suitably profiled cam for cam engagement with a suitable bearing surface on the mounting plate. Alternatively, a hydraulic or pneumatic piston drive could be employed. Various other drive means could equally be employed and are within the scope of this invention.

The drive means preferably drives the probes in a manner which in use, results in reciprocating movement in a vertical plane, preferably from above the enclosure. However, the probes could, for example reciprocate in a vertical plane from below the enclosure, or could reciprocate in a horizontal plane, or other plane as appropriate displaced from vertical.

The apparatus of the invention can employ guide means for guiding the piercing probes in reciprocating movement. Such guide means can include a guide plate having openings through which the probes travel during reciprocating movement. The guide plate can be stationary, such that the probes move relative thereto. The guide means can additionally include guide tubes extending from the guide plate in the direction of reciprocating movement of the probes. The guide tubes can have a length substantially equal to the stroke of the reciprocating probes and can accommodate the piercing ends of the probes when operation of the apparatus is complete, so as to avoid needle stick injuries if the operator needs to place his or her hand into the enclosure, such as for removing the treated ovaries or for cleaning purposes.

The invention also preferably includes abutment means to remove any ovaries that may become stuck to one or more probes. The abutment means can comprise an abutment plate having openings through which the probes can reciprocate, but which are too small to allow the ovaries to follow. The ovaries thus abut against this plate and as the probes continue to retract through the openings the ovaries eventually fall off. The abutment plate could be a plate similar to the guide plate, or could be a mesh screen, or alternatively, the abutment means could be a series of bars extending across the enclosure. In one embodiment, the abutment means comprises an abutment plate and that plate also forms the guide plate of the guide means hereinbefore described. Thus the single plate functions as both guide means and abutment means. Other variations may equally be employed.

In an alternative arrangement, the ovaries may be sandwiched between two grids and the probes extend through the respective grids, during their downward stroke, piercing the ovaries sandwiched therebetween. In this arrangement the upper of the two grids prevents any ovaries from remaining stuck to the probes during the return stroke thereof.

In one arrangement of the invention, the apparatus includes an outer casing into which the other components are seated. The outer casing may fully accommodate each of the other components, or may only partially accommodate those components. The outer casing may include a sleeve which forms the side walls of the enclosure and a base which forms the bottom of the enclosure. The outer casing of this kind may be formed with supports in order to elevate the other components away from the casing base. For example, an enclosure having two compartments may be formed, by elevating the other components away from the base. In that arrangement, the upper compartment may be formed above the supports, while a lower compartment is formed between the base and the upper compartment. In this arrangement, the partition described earlier may rest on the supports elevated above the casing base, so that the lower compartment is formed between the partition and the casing base. In this arrangement, a drainage outlet may also be provided in a lower part of the casing, such as in a side wall adjacent the base or in the base itself. The drainage outlet can be formed in any suitable manner and may employ a suitable tap valve to open and close the outlet. The casing base may be formed to direct liquid toward the outlet, such as by a drainage channel, or by sloping the base toward the outlet.

Preferably the casing can be removed and this may be so that the extracted oocytes can be drained from the casing in a suitable location, and also, to facilitate removal of the treated ovaries and for cleaning purposes. The invention may employ heating means to heat the ovaries, and/or to maintain the ovaries at a particular temperature. Any suitable heating means may be provided such as fan heating or heat pads. It is preferable that the temperature be maintained at between 25°C to 37°C, as this temperature can increase the viability of the oocytes. The attached drawings show an example embodiment of the invention included in an assembly of the foregoing kind. The particularity of those drawings and the associated description does not supersede the generality of the preceding broad description of the invention. Figures 1 and 2 show perspective views of separate component parts of an apparatus according to a first embodiment of the invention.

Figure 3 is an assembled perspective view of the component parts of Figures 1 and 2. Figures 4 and 5 are side views of the apparatus of Figure 3.

Figure 6 is a perspective view of the apparatus of Figure 3. Figure 7 is a further side view of the apparatus of Figure 3. Figure 8 is a side view of an apparatus according to a second embodiment of the invention. Figures 9, 10 and 12 to 16 show component parts of the apparatus shown in Figure 8.

Figure 11 is a part side view of the apparatus of Figure 8. Figure 18 is a view of a comb for use with the invention. Referring to Figures 1 to 3, an apparatus 10 is illustrated. The apparatus 10 includes an outer casing 11 , which surrounds an internal arrangement 12 including a mounting plate 13, a plurality of probes 14, a guide plate 15 and guide tubes 16, an abutment plate 17 and a mesh screen 18. The internal arrangement 12 is shown in Figure 1 separate from the outer casing 11 shown in Figure 2, while the assembled form of the apparatus 10 is shown in Figure 3. In the arrangement illustrated, the outer casing 11 combines with the internal arrangement 12 to form an enclosure 19. The enclosure 19 is formed between the abutment plate 17 and the base 20 of the outer casing 11 and is divided by the mesh screen 18 into an upper compartment 21 and a lower compartment 22. The mesh screen 18 is raised above the base 20 by the provision of corner blocks 23.

The probes 14 are elongate, solid rods that are fixed at one end 24 (see Figures 4 to 7) to the mounting plate 13 in any suitable manner and for example, the probe ends may be adhesively secured within openings (not shown) drilled within the mounting plate 13. The probes are sharpened or pointed at their free end 25 and it is this end 25 that is arranged for piercing the walls of ovaries. The mounting plate 13 and the probes 14 fixed thereto are arranged to reciprocate relative to the other parts of the apparatus 10 and for that purpose, a suitable drive means (not shown) is employed to impart reciprocating movement to the mounting plate. The drive means may take any suitable form, such as a hydraulic or pneumatic drive shaft fixed to the mounting plate, or a cam arrangement.

The probes 14 extend from the mounting plate 13 through a plurality of openings 26 provided in the guide plate 15. In Figures 1 and 3, only two rows of probes extending perpendicular to each other are shown and consequently only two rows of openings 26 are shown. However, the arrangement shown is for illustrative purposes only and in practice, an entire matrix of probes 14 and openings 26 would be provided across the mounting plate 13 and the guide plate 15.

As the name suggests, the guide plate 15 and the guide tubes 16 have a guiding function in relation to the passage of the probes 14 during reciprocating movement thereof. The guide plate 15 and the guide tubes 16 remain stationary relative to the probes 14 and maintain the probes in correct spacing and alignment.

The abutment plate 17 also includes a plurality of openings (which are not visible in Figures 1 and 3) complementary to the openings 26 provided in the guide plate 15. The probes 14 pass through these openings in the abutment plate 17 during reciprocating motion thereof.

Reciprocating movement of the probes 14 causes them to move toward and away from the mesh screen 18. The stroke of the probes 14 can be arranged to suit the ovaries being treated and the stroke may be adjustable in some forms of the invention.

In Figure 3, the upper compartment 21 of the enclosure 19 has a plurality of ovaries 27 laid across the mesh screen 18. The ovaries 27 are inserted into the upper compartment 21 prior to insertion of the internal arrangement 12 into the outer casing 11. The ovaries 27 are fully or partially covered by a liquid solution that fills the lower compartment 22 and the liquid solution facilitates extraction of the oocytes from the ovaries when reciprocating movement of the probes 14 commences. The liquid solution also facilitates damage-free collection of the oocytes in the lower compartment 22 as the oocytes gently fall through the liquid solution under their own weight.

The base 20 of the outer casing 11 includes a drainage outlet 28 for draining the liquid solution from the enclosure 19 during reciprocating motion of the probes, or when the reciprocating motion of the probes 14 has ceased. The base 20 may be configured to slope towards the drainage outlet 28, although this is not shown in the drawings.

Operation of the apparatus 10 is as follows. With the internal arrangement 12 removed from the outer casing 12, the mounting plate 13 is retracted away from the guide plate 15 a distance suitable to remove the sharpened free ends 25 of the probes 14 from the upper compartment 21. Then ovaries 27 are inserted into the upper compartment 21 and a liquid solution is poured into the outer casing 11 , up to the level indicated by the broken line 29 in Figure 3. The internal arrangement 12 is then inserted into the outer casing 11 and the apparatus positioned whereby a suitable drive mechanism can act on the mounting plate 13 to impart a reciprocating movement to the mounting plate and the probes 14 attached thereto. The drive mechanism is activated and the probes commence reciprocation toward and away from the mesh screen 18, thereby piercing the ovary walls on each downward stroke.

The reciprocating movement is illustrated more clearly in Figures 4 to 7. In Figure 4, the mounting plate 13 is fully retracted away from the guide plate 15, such that the free ends 25 of the probes 14 are fully retracted from the enclosure 19. In this condition, with the internal arrangement 12 removed from the outer casing 11 , the ovaries 27 can be placed on a mesh screen 18, while the liquid solution can be poured into the casing 11. The internal arrangement 12 is then inserted into the outer casing 11 and the liquid solution should rise at least to the broken line indicated by the reference numeral 29, but preferably that level should rise above the array of ovaries. In Figure 5, the drive mechanism has driven the mounting plate 13 towards the guide plate 15 and the probes 14 have been driven into the enclosure 19, so as to extend fully through the upper compartment 21. The probes in this position also extend through the ovaries 27, piercing their outer walls. The probes 14 pass fully through the ovaries 27, as shown in this figure. In the embodiment illustrated, it can be seen that the probes 14 extend through the mesh screen 18 at the maximum stroke illustrated in Figure 5. The mesh screen 18, must therefore have sufficient sized openings to enable the probes 14 to pass through and it has been found that quite a coarse mesh can be used, as the primary function of the mesh screen 18 is to prevent the ovaries from entering the lower compartment 22 but to allow the passage of oocytes into that compartment.

Figure 6 is a perspective view of Figure 5 and this shows how the mounting plate has been driven downwardly into the outer casing 11 so that the probes 14 extend into the upper compartment 21 to pierce the walls of the ovaries 27.

Figure 7 shows the upward movement of the mounting plate and probes following piercing of the ovaries. After piercing, the ovaries 27 tend to "stick" to the probes 14 and rise with the probes toward the abutment plate 17. When the ovaries come into contact with the abutment plate 17, they are knocked off the probes and fall back into the liquid solution. The liquid solution cushions the fall of the ovaries so that little or no damage to them occurs. The higher the liquid level within the upper compartment, obviously the less the distance the ovaries have to fall.

The above reciprocating process is repeated many times so that the ovary walls are repeatedly pierced, creating openings in the walls of a sufficient size enabling the oocytes within the ovaries to be released therefrom into the liquid solution. Release of oocytes from within an ovary occurs when an opening of a sufficient size is created in the ovary wall. The oocytes simply pass through the opening created and into the liquid solution contained in the outer casing 11. Turbulence created in the liquid solution by the repeated reciprocation of the probes into and out of the upper compartment 21 , as well as turbulence created by movement within the upper compartment of the ovaries 27, assists the removal of oocytes from within the ovaries, but without such turbulence, the oocytes would still be released upon creation of openings of sufficient size. The turbulence in the lower compartment 22 preferably is minimal, but invariably a certain amount of turbulence is created in the lower compartment simply as a result of that created in the upper compartment, although the level of turbulence in the lower compartment is at a much reduced level than that in the upper compartment. When a sufficient, predetermined time has elapsed, the drive mechanism is turned off or removed from the mounting plate 13 and the internal arrangement 12 is removed from the outer casing 11. The liquid solution remains in the outer casing and can be drained therefrom in order to be treated for removal of the extracted oocytes. An alternative arrangement according to the invention is shown in Fig. 8 and the apparatus 100 shown in this figure includes a pair of funnels 101 and 102 that are connected to a supporting frame structure 103. Each of the funnels 101 , 102 is connected to a respective collection tube 104, 105 for collecting oocytes that are extracted from the ovaries being processed. The connection between the funnels and the respective collection tubes can be made in any suitable manner, such as by a snap connection or a threaded connection, while in Fig. 8, the relevant connection includes a valve 106 disposed between the open end of the funnel 102 and the collection tube 105. The valve 106 can be used to close communication between the funnel 102 and collection tube 105 when it is desirable to remove the collection tube 105 from the funnel 102. Any suitable valve may be employed and in the arrangement shown, the valve is a manually operable butterfly valve, which is operable between open and closed positions by the lever 107.

Ovaries to be processed by the apparatus 100 are placed within a tray 108 which is shown in Figures 9 and 10. Figure 9 shows a side view of the tray 108, while Figure 10 shows the same tray in plan view. As shown, the tray 108 is square in plan view and includes a base 109 and four side walls 110 that depend upwardly from the base 109 and define a receptacle for receipt of the ovaries. The tray 108 further includes a handle 111 for positioning the tray within the apparatus 100.

The base 109 of the tray 108 is constructed of a mesh or grid that includes openings sufficiently large to enable oocytes to pass through, but which are not large enough to allow passage therethrough of an actual ovary. A second mesh or grid may be employed within the funnel 102 to catch any ovaries that, by whatever means, escape from the tray 108. The second grid would be operable to prevent such ovaries from entering and blocking the valve

106 or the collection tube 105, but, like the base 109 of the tray 108, would permit oocytes to pass through.

The tray 108 nests within the open upper end of the funnel 102.

The frame 103 extends upwardly from the funnel 102 and includes facility for connection of a reciprocating arrangement that includes a cylinder

113 and a plunger 114. The frame 103 includes an upward extension member 112, shown in Figures 11 to 13, to which the cylinder 113 that accommodates the plunger 114 is fixed. Figure 12 is a plan view of this arrangement and from that figure, it can be seen that two frame members 112 are bridged by two edge members 115 and a central member 116. Each of the edge members 115 includes openings to receive nut and bolt fasteners, to fasten the edge members, and thus the frame 112, to the frame 103. The central member 116 is formed in a T-shape for stiffness and includes openings 117 for connecting one end of the cylinder 113 thereto. A side view of the arrangement shown in Figure 12 is shown in Figure 13.

The plunger 114 is connected to a bank of probes or needles 118 which is formed by three separate plates shown in Figures 14, 15 and 16. Referring to Figure 14, this shows a plate 119 that can be fixed by suitable fastening means to the lower end of the plunger 114. In Figure 14, an outline of the plunger 114 is shown and the connection to the plate 119 is by nut and bolt fasteners which pass through openings 120 in the plate 119. The plate also includes further openings 121 and these facilitate connection of the plate 119 to the spacer plate 122 of Figure 15 and to the carrier plate 123 of Figure 16. It can be seen that each of the spacer plate 112 and the carrier plate 123 include openings 120 such that nut and bolt fasteners can be extended through each of these openings for connection purposes. The spacer plate of Figure 15 includes a plurality of elongate openings

124. The carrier plate of Figure 16 includes a plurality of round openings 125. The arrangement of the plates shown in Figures 14 to 16 is such as to accommodate a needle 126 formed in the shape shown in Figure 17. In that Figure, the needle 126 includes a leg 127 that depends from a main needle body portion 128, substantially at right angles thereto. Thus, in the arrangement shown, a needle extends through each opening 125 in the carrier plate 123 and the leg 127 thereof is located within an elongate opening 124 of the spacer plate 122. The arrangement is such that, the location of the leg 127 within an elongate opening 124 prevents rotation of the needle 126, while the bent leg 127 is sandwiched between the carrier plate 123 and the plate 119 to secure the needle 126 in place. The needle bank 118 includes a needle 126 for each of the openings 125 of the carrier plate 123. Operation of the apparatus 100 is similar to that of apparatus 10 previously described, in that the plunger 114 raises and lowers the needle bank 118 relative to the ovary tray 108 such that the needles 126 puncture the ovaries within the tray 108 and facilitate release of the oocytes therefrom. Preferably, the stroke of the plunger is such as to extend the needles through the base 109 of the tray 108. A stripper plate 129 (Figure 8) has the same role as the abutment plate 17 previously described, such as to remove ovaries that remain attached to the needles 126 on the upward stroke of the plunger 114.

The apparatus 100 is filled with a media suitable for the collection of oocytes and the media is filled to a level above the upper openings of each of the funnels 101 and 102, so that there can be media transfer between those funnels. During operation of the apparatus 100, oocytes are released from the ovaries and fall downwardly into the funnel 102 for collection within the collection tube 105. However, some oocytes will be deflected into the funnel 101 and these are collected within the collection tube 104. When the operation is complete, valve 106 may be closed and the collection tube 105 containing the majority of oocytes removed. Oocytes can also be removed from the collection tube 104 when the media within the funnels 101 and 102 is drained.

It should be appreciated that the existence of the funnel 104 is optional only. Indeed, it is expected that the apparatus 100 can operate quite adequately with the single funnel 102 and therefore the existence of the funnel 101 is preferred only.

The plunger arrangement 113, 114 can be operated in any suitable manner, such as by pneumatic or hydraulic fluid, or by an electric motor. Additionally, the arrangement of the needle bank 118 could also take a different form suitable to securely locate a plurality of needles. With respect to the type of needles used, the preferred arrangement is for solid wire needles, although hollow needles could alternatively be used. The stripper plate provided in the apparatus 100 has a similar configuration to the carrier plate 123, in that it has a plurality of openings through which each needle extends. The openings are of a similar size to those of the carrier plate and are of a slightly greater diameter than the diameter of the needles 126 and the stripper plate therefore also acts as a guide for each needle 126. Such a guide is preferable, to ensure that the needles do not deviate from the necessary trajectory for them to pass through the mesh base 109 of the tray 108. The stripper/guide plate arrangement works well, however when the apparatus 100 is disassembled either for cleaning or maintenance purposes, it is very difficult to realign each needle to pass through the openings in the stripper plate. Thus, applicant has developed a unique system for aligning the needles and that involves the use of a comb 130 which is shown in Figure 18. The comb includes a plurality of teeth 131 and the teeth are spaced apart by a series of gaps 132. To align the needles 126, a first comb is threaded through the grid of needles in one direction, after which a second comb is threaded through the needles at 90° to the first comb. Each needle is therefore captured between crossing teeth which readily align the teeth for insertion through the stripper/guide plate.

EXAMPLES The table below lists two experimental runs using apparatus according to the Figures 1 to 7 compared to the conventional aspiration method (control).

Each of runs 1 and 2 was performed under the same conditions, using

100 plunges of the probes and the same liquid collection solution. In each run, the apparatus recovered an equal number of oocytes as compared to the conventional aspiration (5-6 oocytes/ovary), while the blastocyst percentage was comparable to the aspiration control.

The table below provides a comparison of the ratio of ova (oocyte)/ovary and the quality of ova obtained from an apparatus of the kind shown in Figures 8 to 18, which is known as an Ova Harvester, and from traditional aspiration.

KEY OH = Ova Han/ester Cont = Aspiration

This table shows that there is no significant difference between the number of ova obtained, or the quality of the ova between the traditional method of aspiration, as compared to the Ova Harvester.

The invention described herein is susceptible to variations, modifications and/or additions other than those specifically described and it is to be understood that the invention includes all such variations, modifications and/or additions which fall within the spirit and scope of the above description.

Claims

CLAIMS:

1. A method of extracting oocytes from ovaries, said method including placing a plurality of ovaries in an enclosure and repeatedly piercing the walls of the ovaries with a plurality of probes which move in a reciprocating motion in the enclosure, the repeated piercing of the ovary walls creating a plurality of openings through which oocytes within the ovaries can pass into the enclosure for collection.

2. A method according to claim 1 , said enclosure including a base on which said plurality of ovaries are placed, said base including a plurality of openings through which extracted oocytes can pass, said method including collecting said extracted ovaries in a collection facility of said enclosure below said base.

3. A method according to claim 2, liquid being provided in said collection facility below said base in order that said extracted oocytes fall through said liquid prior to collection, whereby said liquid minimises damage to said extracted oocytes prior to their collection.

4. A method according to claim 3, said liquid having an upper level above said base so that said ovaries are at least partly immersed within said liquid when they are supported on said base.

5. A method according to any one of claims 1 to 4, further including heating means to maintain an elevated temperature.

6. A method according to claim 5, said elevated temperature being in the range of between 25°C to 37°C .

7. A method according to any one of claims 1 to 6, said probes being driven to reciprocate through a stroke sufficient to extend completely through said ovaries and said base on which said ovaries are supported permitting at least the tips of said probes to extend therethrough.

8. An apparatus for extracting oocytes from ovaries, said apparatus including an enclosure for receiving a plurality of ovaries and a plurality of probes for repeatedly piercing the walls of the ovaries which are drivable by drive means in a reciprocating motion in the enclosure, repeated piercing of the ovary walls creating a plurality of openings through which oocytes within the ovaries can pass into the enclosure for collection.

9. An apparatus according to claim 8, said enclosure being divided into vertically spaced upper and lower compartments separated by a partition, said upper compartment being provided to receive said ovaries and said lower compartment being provided for collection of extracted oocytes, said partition permitting said extracted oocytes to pass from said upper chamber to said lower chamber.

10. An apparatus according to claim 9, in use, said lower compartment being filled with a liquid that extracted oocytes can fall through under gravity to minimise damage to said oocytes prior to their collection.

11. An apparatus according to claim 10, said liquid extending into said upper chamber to at least partly immerse said ovaries.

12. An apparatus according to any one of claims 9 to 11 , said partition being formed by a mesh screen, the openings of which permit passage therethrough of extracted oocytes but prevent passage therethrough of ovaries.

13. An apparatus according to any one of claims 8 to 12, said probes being of elongate, needle-like construction, one end of which is fixed to a mounting plate and the other end being sharpened for piercing the walls of said ovaries.

14. An apparatus according to claim 13, said mounting plate being drivable in a reciprocating motion to cause said probes to reciprocate.

15. An apparatus according to any one of claims 8 to 14, said probes being driven to reciprocate in a vertical plane.

16. An apparatus according to any one of claims 8 to 14, said probes being driven to reciprocate in a plane displaced from vertical.

17. An apparatus according to any one of claims 8 to 16, further including guide means for guiding said probes in a reciprocating manner.

18. An apparatus according to claim 17, said guide means including a guide plate having openings through which said probes reciprocate.

19. An apparatus according to any one of claims 8 to 18, further including abutment means to cause removal of ovaries from said probes on the upward stroke of the probes during reciprocating movement.

20. An apparatus according to claim 19, said abutment means including an abutment plate, said abutment plate including openings within which said probes can reciprocate, but which are smaller than would permit an ovary to pass through.

21. An apparatus according to any one of claims 8 to 21 , a funnel being provided for collection of said extracted oocytes, said funnel communicating with a collection tube and valve means being disposed between said funnel and said collection tube, said valve means controlling outflow of liquid from said funnel upon removal of said collection tube.

22. An apparatus according to claim 21 , an ovary barrier being provided within said funnel to prevent ovaries from entering and blocking the narrow neck of said funnel or said valve means, said ovary barrier being positioned below the surface on which the ovaries are supported and permitting passage therethrough of extracted oocytes.