The efficacy of cryopreserved hamster ova in the sperm penetration assay.
To solve the logistical problems of the sperm penetration assay (SPA) to provide just a sufficient number of hamster ova exactly when they are needed, a new method to cryopreserve the ova has been devised. The ova, suspended in a 1.5 M solution of propylene glycol as a cryoprotectant in an isotonic salt solution, were frozen in 1/4 mL plastic straws. Included in each straw was a sucrose solution, isosmotic to the propylene glycol solution, to serve as an osmotic buffer during dilution of the cryoprotectant out of the ova. This one-step method of dilution permitted the ova to be recovered and diluted out of the cryoprotectant within the straw in which they had been originally frozen. A total of 547 cryopreserved ova were thawed, 504 (92.1%) of which were morphologically normal after they had been incubated at 37 degrees C for 3 hours. After removal of the zonae, the frozen-thawed ova were compared with fresh, control ova in SPAs of donor and patient semen that had been capacitated in TEST-yolk buffer. The percent penetration and penetration index of fresh versus cryopreserved ova did not differ significantly for either donor or patient semen.
Leibo
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SP
Rio Vista International, San Antonio, Texas.
Giambernardi
T A
TA
Meyer
T K
TK
Bastias
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MC
Rogers
B J
BJ
D000704:Analysis of Variance; D000818:Animals; D006224:Cricetinae; D015925:Cryopreservation; D005260:Female; D006801:Humans; D007248:Infertility, Male / Q000503:physiopathology; D008297:Male; D010063:Ovum; D012016:Reference Values; D013084:Sperm-Ovum Interactions