Study On The Induced Expression Of Bacillus Subtilis For SBD-1 In Cultured Ruminal Epithelial Cells Of Sheep

Defensins are a class of small molecules cationic endogenous antimicrobial peptides which are rich in cysteine, they are widely distributed in nature as the largest family of endogenous antimicrobial peptides. The expression of (3-defensin is the largest in ovine ruminal epithelium. And probiotics can improve immunity by their effect on the epithelial cells. In this study, the ovine ruminal epithelium were cultured in vitro and bacillus subtilis was selected to investigate its effect on the β-defensin expression of ovine ruminal epithelium. Firstly, the ovine ruminal epithelium were cultured successfully in vitro, then the epithelial cells were stimulated with different concentrations of bacillus subtilis at different times, the expression of SBD-1 mRNA and protein were determined by realtime fluorescence quantitative PCR (RT-PCR) and ELISA.The results indicated that the expression of SBD-1 peaked at 8h at the concentration of 1010 cfu/mL. The expression of SBD-1 was increased significantly after stimulating at different concentrations, and the expression at the concentration of 109、1010、1011 cfu/mL showed stronger induction response than the blank (P< 0.01). And the results of protein levels were consistent with the results of mRNA levels. Multiple signalling pathways such as p38 MAPK、JNK and ERK 1/2 may mediate SBD-1 gene expression, and p38 MAPK pathway is the main pathway.