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

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 H₂O₂ 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 H₂O₂ when compared with SS, whereas the effects were similar to SeMet.

Keywords: antioxidant capacity; bovine mammary epithelial cell; hydroxy-selenomethionine; oxidative stress.

Figure 1

Effect of culture time with different Se sources on cell survival rate (A), SOD activity (B), GSH-Px activity (C) and CAT activity (D) of BMEC. All values shown are mean ± SEM from three independent experiments. Different letters in the same Se treatment denote significant differences among culture time.

Figure 2

Effect of different Se sources and HMSeBA levels on protection of BMEC against H₂O₂ induced oxidative stress. (A) DCFH-DA oxidation ratio; (B) Malondialdehyde; (C) DCFH-DA oxidation; (D) Malondiadehyde. Nega Con, negative control (no H₂O₂ and no Se); Posi Con, positive control (no Se, H₂O₂ treatment); SS100, 100 nM sodium selenite supplementation; SeMet100, 100 nM selenomethionine supplementation; HM20, 20 nM hydroxy-selenomethionine supplementation; HM50, 50 nM hydroxy-selenomethionine supplementation; HM100, 100 nM hydroxy-selenomethionine supplementation; HM150, 150 nM hydroxy-selenomethionine supplementation. All values shown are mean ± SEM from three independent experiments. Different letters denote significant differences between treatments.