Preservation of the Reproductive Potential by Freezing and Transplanting Ovarian Tissue in the Domestic Bitch
N.N.E. Gómez; C.G. Gutiérrez; R.M. Páramo
Department of Reproduction, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de Mexico
Freezing and transplantation of ovarian tissue can become an important tool to rescue wild animal's reproductive potential. The domestic bitch was used as an experimental model because its similarities to the wild canids. Thirty bitches were ovariohysterectomized and their ovaries recovered. Age and reproductive status of the bitches was noted. A total of 35 ovarian cortex samples (5x5x2 mm pieces) were frozen in TCM-19 medium supplemented with 10% FCS and 1.5M DMSO and stored in liquid nitrogen. Follicles were mechanically dissected, in both thawed and fresh tissue and their viability evaluated both before and after freezing. Follicular was evaluated after staining them with 0.4% trypan blue solution and observed at 400x in an inverted microscope. Dead follicles will uptake the dye whilst those alive will not. Percentages of live follicles before and after freezing were 92.79 ±6.63% and 50.49 ± 9.03%, age had no significant effect on these results. Survival probabilities calculated by logistic regression were around 50%. In addition, 5 adult bitches were auto-transplanted with frozen-thawed ovarian cortex that was recovered 3 months later Primordial, primary and secondary follicles were identified in 3 of the 5 implanted bitches, as well as early antral follicles in one of the animals. It is concluded that canine follicles can survive freezing, thawing and implantation procedures.