Manganese Provides Antioxidant Protection for Sperm Cryopreservation that May Offer New Consideration for Clinical Fertility

Abstract

Reactive oxygen species (ROS) are generated by sperm metabolism. While, ROS are required for maturation, capacitation and acrosome reaction, they also modify many peroxidable cellular compounds. There is production of ROS during cryopreservation and frozen spermatozoa are highly sensitive to lipid peroxidation (LPO). Antioxidants exert a protective effect on the plasma membrane of frozen bovine sperm preserving both metabolic activity and cellular viability. Manganese (Mn++) is proved to be a chain breaking antioxidant in biological system. Therefore, we examined the role of (Mn++) during cryopreservation of cattle bull semen. Semen was divided into four parts and cryopreserved in egg-yolk-citrate extender + glycerol (EYC-G), EYC-G + 100 µM of Mn++, EYC-G + 150 µM of Mn++ and EYC-G + 200 µM of Mn++. After four hours of cooling and 24 hrs of freezing, the spermatozoa were examined for percentage motility, Hypo-osmotic swelling (HOS), LPO and protein leakage. Addition of manganese to the semen during cryopreservation showed a protective effect and accounted for an increase in semen quality parameters [percentage motility, HOS percent and decrease in malondialdehyde (MDA) production and protein leakage]. The effect of manganese on motility and HOS was non-significant (p < 0.05) in cooled spermatozoa but significant with 150 µM of Mn++ in frozen-thawed spermatozoa. MDA production and protein leakage decreased to a significant and maximum level (p < 0.05) on addition of 200 µM of manganese. The addition of manganese to EYC-G dilutor will improve the quality/fertility of semen, which will result in improvement of in vitro fertilization and artificial insemination success rate.

Influence of Adding Manganese to Tris Extender on some Post-Cryopreservation Semen Attributes of Holstein Bulls

“…The current results also agreed with Cheema et al [22] who found that the addition of Mn +2 (150 µM) to egg-yolkcitrate extender increased PC individual motility (58.3%) in comparison with those of control group (45%). Similar authors found that the addition of Mn +2 to Tris extender improved PC plasma membrane integrity (30.1%) in comparison with the control group (19.7%).…”

Regulation of Manganese Antioxidants by Nutrient Sensing Pathways in Saccharomyces cerevisiae

“…Elegant work by Daly and colleagues has shown that tolerance to radiation and oxidative stress in a variety of bacterial species is due to accumulation of high levels of intracellular Mn, but low Fe (Daly 2006(Daly , 2009Daly et al 2007Daly et al , 2010Gross 2007;Granger et al 2011). In higher organisms, Mn treatment can prolong the life span and oxidative stress resistance in the simple metazoan, Caenorhabditis elegans, and also defend against reactive oxygen species (ROS) in the cryopreservation of sperm (Lin et al 2006;Bansal and Kaur 2009;Cheema et al 2009). …”

Functional features and protein network of human sperm-egg interaction

“…The remainder are common signal transduction and receptor activities. Manganese is an anti-oxidant that prevents the damaging effects of oxidative stress (OS) and has been used to improve the in vitro environment to aid successful IVF or ICSI (Intra Cytoplasmic Sperm Injection) [Cheema et al 2009]. Our results show that the manganese ion transport activity is an important molecular function for sperm-egg interaction that if supressed finally leads to infertility.…”