Effect of Different Vitrification Techniques on Viability and Apoptotic Index of Domestic Cat Testicular Tissue Cells

SIMPLE SUMMARY: The vitrification process stands out among cryopreservation methods because it is a practical and fast technique that reduces the risk of intracellular ice formation and cell damage. The present study aimed to compare three devices used for the vitrification of adult cat testicular biopsies for use in preservation programs. The efficiency of the methods was evaluated by histological and viability analysis of the testicular cells after the vitrification process. It is shown that these methods are efficient and can be considered an important tool for the genetic conservation of endangered wild cats, with the domestic cat providing an experimental model for the development of reproductive biotechnology in wild cat species. ABSTRACT: Vitrification is essential for successful tissue cryopreservation and biobanking in wild cats. This study aimed to compare different methods of vitrification (Ovarian Tissue Cryosystem—OTC, Straws—STW, and Solid Surface vitrification—SSV) for testicular fragment vitrification in tom cats. Testicular fragments were recovered from five adult tom cats and subjected to equilibrium vitrification using different cryovials and methods under the same conditions of vitrification solutions and cryoprotectants. The efficiencies of the methods were evaluated using histological analysis of spermatogonia and Sertoli cell nuclei, seminiferous tubular basement membrane detachment, and the gonadal epithelium shrinkage score scale. Cell viability was assessed using Hoechst PI and Terminal deoxynucleotidyl transferase nick end labeling (TUNEL) assay. The results showed that OTC is an effective vitrification method for maintaining the distinction between spermatogonia and Sertoli cells. OTC was similar to the control for basal membrane detachment parameters (p = 0.05). Epithelial shrinkage was low in the SSV group, which showed the highest percentage of viable cells among the vitrified groups (p = 0.0023). The OTC and SSV vitrification methods were statistically similar in terms of the percentage of TUNEL-positive cells (p = 0.05). Therefore, OTC and SSV provide favorable conditions for maintaining viable cat testicular tissue cells after vitrification.