Comparison of Selenium Source in Preventing Oxidative Stress in Bovine Mammary Epithelial Cells

SIMPLE SUMMARY: Selenium (Se) is recognized as an essential trace element in maintaining antioxidant status in humans and animals. Se supplementation in the diets of livestock exist in two forms: Organic and inorganic forms. The organic Se source hydroxy-selenomethionine (HMSeBA) has been proven to be more biologically efficient than inorganic Se to improve antioxidant capacity when fed to dairy cows, since its approval as a feed additive by the European Commission in 2013. However, information on the comparison between HMSeBA and other Se sources in preventing oxidative stress in bovine mammary epithelial cells (BMEC) is limited. The current study compared the effects of HMSeBA, selenomethionine (SeMet) and sodium selenite (SS) on antioxidant capacity and the ability to resist oxidative stress induced by H(2)O(2) in BMEC. HMSeBA was shown to enhance cellular antioxidant status to resist oxidative damage when compared with SS, but there was no difference between HMSeBA and SeMet. The results of this study provide more information for antioxidant potential of different Se sources in BMEC. ABSTRACT: Oxidative stress can cause cell damage. Hydroxy-selenomethionine (HMSeBA) is an organic Se source with emerging antioxidant advantages. The objective of this study was to compare the effects of HMSeBA, selenomethionine (SeMet) and sodium selenite (SS) on the antioxidant response and the ability to resist oxidative stress in bovine mammary epithelial cells (BMEC). The BMEC were treated with 0 (Control), 20, 50, 100 and 150 nM HMSeBA, 100 nM SeMet and100 nM SS for 48 h. The results showed that HMSeBA and SeMet treatments had higher glutathione peroxidase (p < 0.01) and catalase (p = 0.01) activities and mRNA abundance of GPX3 (p = 0.02), but lower superoxide dismutase activity compared with SS (p = 0.04). The catalase activity (p < 0.05) and mRNA abundance of GPX3 (p = 0.04) changed in a quadratic manner with the increase of HMSeBA levels. To assess the potential protection of different Se sources against oxidative stress on BMEC, 0 or 50 μM H(2)O(2) was added to BMEC culture for 3 h after Se pre-treatment for 48 h. The results showed that HMSeBA and SeMet, which did not differ (p > 0.05), but further decreased malondialdehyde and reactive oxygen species production compared with SS (p < 0.05). In conclusion, HMSeBA showed an enhanced cellular antioxidant status to resist oxidative damage induced by H(2)O(2) when compared with SS, whereas the effects were similar to SeMet.