Comparison of vitrification and slow freezing for cryopreservation of canine ovarian tissue

Abstract

Assisted reproductive techniques such as intracytoplasmic sperm injection (ICSI) and gamete/gonadal tissue cryopreservation are plausible alternatives to overcome physical or behavioral problems that interfere with reproduction. Cryopreservation of gonadal tissues enables the preservation of the genetic material of any animal species that may be submitted to gonadectomy by therapeutic indication, or even that die unexpectedly. However, there is a scarce literature on cryopreservation of gonadal tissue in domestic mammals, especially in the canid family. Taking into account the similarity of the reproductive physiology of domestic bitches with their counterparts, the establishment of cryopreservation protocols would be considered an important step in the conservation of endangered wild canid species. The aim of this project is to compare the techniques of vitrification and a modified slow freezing technique (Tavares et al., 2017) to cryopreserve canine ovarian tissue. For that purpose, ovaries will be collected by ovariohysterectomy from 14 anestrous bitches and will be sectioned in small pieces. The ovarian fragments will be submitted to either vitrification or slow freezing method, and some will be used as control. Evaluation of ovarian tissue will be made by histology and immunohistochemistry (caspase-3). (AU)