QUALITY OF SPERMATIC CELLS OBTAINED FROM CRIOPRESERVED CAT TESTICULAR TISSUE

Abstract

Purpose: Crypreservation of testicular tissue is an important tool for conservation of genetic material, especially from animals that are threatened with extinction, such as the Felidae family. The aim of this study was to evaluate the quality of spermatic cells cryopreserved with two different cryoprotectants. Methods: Testicles were obtained from ten cats submitted to elective orchiectomy at the Veterinary Hospital at UNIFRAN. The testicles were transported in 0.9% NaCl solution at room temperature to the laboratory and were sectioned in small fragments. Then, they were placed in cryotubes containing 1mL Egg yolk Tris Equex STM extender with 3% of glycerol or 3% propanediol for 10 min at room temperature; were maintained at 4°C for 30 min and finally, were laid horizontally on a rack 4 cm above the liquid nitrogen vapour for 10 min, before being plunged into liquid nitrogen. The samples were thawed by exposure to air for 10 sec, submerged into 37°C water bath for 30 sec and incubated in extender medium at 37oC for 5 min. Frozen-thawed fragments were evaluated for DNA integrity through acridine orange dye. Results: There was a significant difference in DNA damage between fragments cryopreserved in propanediol (0.60 ±0.07) and glycerol (0.37 ±0.03), which might be explained by the difference in the perfusion rate into the tissue. Conclusion: Glycerol was considered the best cryoprotectant than propanediol, because provided more cellular stability.