B. Demirci et al., Follicular viability and morphology of sheep ovaries after exposure to cryoprotectant and cryopreservation with different freezing protocols, FERT STERIL, 75(4), 2001, pp. 754-762
Objective: To test the toxicity of cryoprotectant in sheep ovarian tissue a
nd to determine optimal conditions for freezing hemiovary cortex.
Design: Small follicles (<60 <mu>m in diameter) were isolated enzymatically
for viability testing. Dead and live follicles were identified by using tr
ypan blue staining, and follicle morphology was examined histologically.
Setting: Centre hospitalo-universitaire de Biologie de la Reproduction, Hop
ital Edouard Herriot, Lyon, France.
Animal(s): Lambs 5 to 6 months of age.
Intervention(s): Two-millimetre slices of hemiovarian cortex were prepared
for cryoprotectant toxicity tests and freezing procedures.
Main Outcome Measure(s): Follicular mortality and histologic structure.
Result(s): For freezing procedures, the concentration of cryoprotectant was
increased to 2 M on the basis of results of cyoprotectant toxicity tests i
n fresh tissues. Follicular mortality rates were 4.6% with of 2 M dimethyl
sulfoxide (DMSO) and 3.8% with 2 M of propylene glycol (PROH). After freezi
ng with semiautomatic seeding, follicular mortality rates were 8.38 (2 hi o
f DMSO) and 12.4% (2 M of PROH). Tissue morphology was well preserved with
1.5 M of DMSO or PROH. With 1.5 M DMSO, results of the slow cooling protoco
l (2 degreesC/min) without seeding and the standard very slow cooling proto
col (0.3 degreesC/min) were similar.
Conclusion(s): Optimal survival of primordial follicles in the sheep was ob
tained by using a slow tooling protocol with semiautomatic seeding at 2 hi
of DMSO, (Fertil Steril (R) 2001;75:753-62. (C) 2001 by American Society fo
r Reproductive Medicine.).