The effects of addition of vitamin B12 in semen cryopreservation medium on the post-thaw sperm function

Introduction & Objectives: Cryopreservation may lead to deleterious changes of sperm structure and function (such as decreasing Motility, viability and increasing DNA damage). Vitamin B12 has antioxidative properties and can protect DNA from free radicals. Vitamin B12 also plays important role in DNA methylation. Recent studies revealed that vitamin B12 may modulate oxidative stress responses through enhancing methionine synthase activity that is linked to glutathione synthesis—a major intracellular antioxidant. In addition, vitamin B12 might act directly as a scavenger of ROS. The objective of this study was to investigate the effects of vitamin B12 supplementation in human sperm quality during the freezing-thawing process.Materials & Methods: Thirty Semen samples were collected from men with normal sperm parameters and were assessed according to World Health Organization guidelines. Following semen liquefaction, each sample was diluted (v/v) with Cryosperm that contained different concentrations of vitamin B12 (.5, 1, 2, 2.5 mg/ml). The diluted semen samples were drawn into straws and froze. After thawing, all samples were evaluated for motility and viability. Based on results, 2 mg/ml was considered as the optimal concentration of vitamin B12 for evaluating sperm DNA fragmentation. The data analyzed by one-way ANOVA and Tukey post-test (P<0.05).Results: The results showed that 2 mg/ml vitamin B12 significantly increased motility and viability post-thawing compared to the control (p<0.05). Also the concentration of 2 mg/mL vitamin B12 decreased DNA fragmentation compared to the control.Conclusion: The increased motility, viability sperm were probably due to increasing antioxidant status by increasing of glutathione peroxidase activities, which would give protection against spontaneous lipid peroxidation. It also leads to decreasing of ROS and DNA fragmentation. The present study showed that vitamin B12 supplemented freezing media can improve sperm quality after freezing/thawing.

کلیدواژه ها:

cryopreservation ، vitamin B12 ، DNA fragmentation