Selenium (Na 2 SeO 3 ) Upregulates Expression of Immune Genes and Blood–Testis Barrier Constituent Proteins of Bovine Sertoli Cell In Vitro

Sertoli cells were isolated from newborn calves and cultured in a medium supplemented with 0, 0.25, 0.50, 0.75, and 1.00 mg/L of sodium selenite to study their immune stimulatory effect, influence on cell’s viability, and expression of blood–testis barrier proteins (occludin, connexin-43, zonula occluden, E-cadherin) using quantitative PCR and western blot analyses. Results showed that medium supplemented with 0.50 mg/L of selenium significantly (P < 0.05) promoted cell viability, upregulated toll-like receptor gene (TLR4), anti-inflammatory cytokines (IL-4, IL-10, TGFβ1), and expressions of blood–testis barrier proteins, and modulated expressions of pro-inflammatory cytokines (TNF-α, IL-1β, IFN-γ). Sertoli cells grown in culture medium supplemented with 0.25 mg/L of selenium significantly upregulated TLR4, IL-4, IL-10, TGFβ1, and blood–testis barrier proteins compared to the control group. Sodium selenite supplementation at 0.75 and 1.00 mg/L levels was cytotoxic and temporarily downregulated the expression of blood–testis barrier protein within 24 h after culture; however, commencing from 72 h post culture, increased cell viability and upregulation of expression of blood–testis barrier proteins were observed. In conclusion, the results of this study showed that selenium supplementation in the culture medium up to 0.50 mg/L concentration upregulates immune genes and blood–testis barrier constituent proteins of bovine Sertoli cells.