Cryopreservation of isolated ovine primordial follicles with propylene glycol and glycerol.

Objective: To verify the viability of isolated primordial follicles to different propylene glycol (PROH) and glycerol (GLY) concentrations before and after cryopreservation. Design: Isolated primordial follicles were stained with trypan blue to evaluate the effect of different PROH and GLY concentrations before and after cryopreservation. Setting: Laboratorio Renzo Giuliani, University of Florence, Italy. Patient(s): Thirty- to forty-day-old lambs. Intervention(s): Isolation of primordial follicles with subsequent exposure to cryoprotectant and freezing. Main Outcome Measure(s): Histologic structure and follicular mortality. Result(s): After the isolation procedure (control), the mean number of live primordial follicles/mL was 2,688 and 4,452 in the GLY and PROH groups, respectively. When GLY was used, the number of live follicles before cryopreservation was 820, 756, 640, 524, 564, and 460 follicles/mL with concentrations of 0, 0.5, 1.0, 1.5, 2.0, and 2.5 mol/L, respectively. After cryopreservation, this number decreased to 0, 12, 36, 100, 84, and 68 follicles/mL, respectively, with the same concentrations. When PROH was used, the number of live follicles before cryopreservation was 4,216, 3,880, 3,560, 1,812, 704, and 568 follicles/mL with concentrations of 0, 0.5, 1.0, 1.5, 2.0, and 2.5 mol/L, respectively. After cryopreservation, this number decreased to 0, 116, 336, 472, 360, and 244 follicles/mL, respectively, with the same concentrations. Conclusion(s): Both cryoprotectants were shown to preserve isolated primordial follicles after cryopreservation. (Fertil Steril 2004;81(Suppl 1):735– 40. ©2004 by American Society for Reproductive Medicine.)