Low-Temperature Equilibration Impairs Follicular Preservation in Vitrified Domestic Cat Ovarian Tissue

Ovarian tissue vitrification holds great promise as a preservation technique for endangered wild felids; however, the development of an optimal protocol remains desired. One potential factor affecting success is the equilibration temperature and its impact on follicular survival. We hypothesised that optimizing the equilibration conditions at low temperatures would enhance vitrification yield in domestic cat. To test this, we first optimised the equilibration time in a four-step protocol involving progressively decreasing temperatures. We then validated this approach through a comparative study against a room-temperature equilibration protocol. Contrary to our expectations, the cold equilibration strategy did not improve follicular survival, challenging previous assumptions about its potential benefits. This study provides new insights into the role of equilibration temperature in feline ovarian tissue vitrification and contributes to refining cryopreservation strategies for felids.