The effects of vitamin E supplementation on sperm parameters, chromatin integrity, and gene expression before and after freezing in aged mice

Objective: Some age-related testicular changes, such as Sertoli cell vacuolization and blood–testis barrier breakdown, reduce total sperm production and male fertility. Therefore, this study investigated the effect of vitamin E on restoring testicular function in aged mice. Sperm cryo-resistance was also assessed. Methods: Twenty-eight 48-week-old male Naval Medical Research Institute mice were divided into four groups for a daily gavage of vitamin E: the control group received distilled water, while the three treatment groups were administered 100, 200, and 400 mg/kg, respectively, for 4 weeks. Subsequently, semen analyses, DNA fragmentation index (DFI), and protamine deficiency tests were conducted. Testicular histology, tissue antioxidant enzyme activity, and gene expression levels were also assessed.Results: The two higher dosages of vitamin E were associated with a higher sperm count, greater progressive motility, and improved sperm morphology (pppp<0.05). Conclusion: Antioxidant supplementation might enhance reproductive outcomes in aging males. The observed effects included improved sperm cryo-resistance, which is advantageous for future applications such as sperm freezing or fertility preservation.