Cryopreservation of ovine primordial follicles using dimethyl sulfoxide.

Objective : To verify the viability of isolated primordial follicles after exposure to different concentrations of dimethyl sulfoxide (DMSO) and after cryopreservation. Design : Randomized control trial. Setting : Laboratorio Renzo Giuliani, University of Florence, Italy. Animal(s) :Thirty- to 40-day-old lambs. Main outcome measure(s) : Isolated primordial follicles were stained with trypan blue to evaluate the effect of different DMSO concentrations before and after the cryopreservation. Histological structure and follicular mortality were evaluated. Result(s) : After the isolation procedure (control), a mean (±SE) of 800 ± 203.86 live primordial follicles/mL were obtained. The number of live follicles in the toxicity test using the DMSO at 0, 0.5, 1.0, 1.5, 2.0, and 2.5 M was 782 ± 193.96, 754 ± 172.03, 778 ± 191.58, 736 ± 191.92, 476 ± 122.9, and 316 ± 83.52, respectively. The number of live follicles at 2.5 M was lower than that in the control procedure. After cryopreservation, the numbers decreased to 0 ± 0, 232 ± 44.20, 636 ± 161.82, 628 ± 181.28, 208 ± 11.57, and 184 ± 47.07, respectively at 0, 0.5, 1.0, 1.5, 2.0, and 2.5 M. The number of live follicles at 0, 0.5, 2.0, and 2.5 M were lower than that in the control procedure.