Proteomics of intracellular freezing survival

Enhanced cell survival in prepubertal testicular tissue cryopreserved with membrane lipids and antioxidants rich cryopreservation medium

The present study explores the advantages of enriching the freezing medium with membrane lipids and antioxidants in improving the outcome of prepubertal testicular tissue cryopreservation. For the study, testicular tissue from Swiss albino mice of prepubertal age group (2 weeks) was cryopreserved by slow freezing method either in control freezing medium (CFM; containing DMSO and FBS in DMEM/F12) or test freezing medium (TFM; containing soy lecithin, phosphatidylserine, phosphatidylethanolamine, cholesterol, vitamin C, sodium selenite, DMSO and FBS in DMEM/F12 medium) and stored in liquid nitrogen for at least one week. The tissues were thawed and enzymatically digested to assess viability, DNA damage, and oxidative stress in the testicular cells. The results indicate that TFM significantly mitigated freeze-thaw-induced cell death, DNA damage, and lipid peroxidation compared to tissue cryopreserved in CFM. Further, a decrease in Cyt C, Caspase-3, and an increase in Gpx4 mRNA transcripts were observed in tissues frozen with TFM. Spermatogonial germ cells (SGCs) collected from tissues frozen with TFM exhibited higher cell survival and superior DNA integrity compared to those frozen in CFM. Proteomic analysis revealed that SGCs experienced a lower degree of freeze-thaw-induced damage when cryopreserved in TFM, as evident from an increase in the level of proteins involved in mitigating the heat stress response, transcriptional and translational machinery. These results emphasize the beneficial role of membrane lipids and antioxidants in enhancing the cryosurvival of prepubertal testicular tissue offering a significant stride towards improving the clinical outcome of prepubertal testicular tissue cryopreservation.