Abstract: The aim of this study was to investigate the effects of selenium-oligochitosan against zearalenon (ZEN) on the expression of tight junction protein of IPEC-J2 cells. The experiment was divided into control group (C), ZEN (30 μg/mL), ZEN+0.5 Se (30 μg/mL ZEN+0.5 μmol/L selenium-oligochitosan, in terms of Se), ZEN+1.5 Se and ZEN+3 Se groups. When the confluence of cells reached 60%-70%, the culture medium of ZEN+0.5 Se, ZEN+1.5 Se and ZEN+3 Se groups was replaced with the culture medium containing the corresponding Se concentration, C and ZEN groups were replaced with normal culture medium. After 12 h, 30 μg/mL ZEN was added to the ZEN-containing groups, and the culture was continued for 24 h. The cell culture medium of each group was collected to detect the activity of alkaline phosphatase (AKP), the expressions of zonula occludens-1(ZO-1) and Occludin were detected by Western blotting, the expression and localization of ZO-1 and Occludin proteins were detected by immunofluorescence. The results of AKP activity showed that compared with control group, the AKP activity was significantly increased in ZEN, ZEN+0.5 Se and ZEN+1.5 Se groups (P<0.05), but there was no significant difference in ZEN+3 Se group (P>0.05). Compared with ZEN group, the AKP activity of ZEN+1.5 Se and ZEN+3 Se groups was significantly reduced (P<0.05). Western blotting results showed that compared with control group, the protein expression levels of ZO-1 and Occludin in ZEN group were significantly decreased (P<0.05). When compared with ZEN group, there were no significant differences in ZO-1 expression levels in ZEN+0.5 Se, ZEN+1.5 Se and ZEN+3 Se groups (P>0.05), but with the increase of Se concentration, the protein expression level of ZO-1 was gradually increased, the protein expression level of Occludin was significantly increased in ZEN+0.5 Se, ZEN+1.5 Se and ZEN+3 Se groups (P<0.05). The immunofluorescence results showed that selenium-oligochitosan could relieve the decreased fluorescence signal of ZO-1 and Occludin caused by ZEN, and restore the location distribution of the proteins. In conclusion, selenium-oligochitosan could reduce the increase of AKP activity in IPEC-J2 cells caused by ZEN, up-regulate the decreased expression levels of ZO-1 and Occludin in IPEC-J2 cells caused by ZEN, and adjust its location distribution.

Key words: zearalenone; selenium-oligochitosan; porcine intestinal epithelial cell (IPEC-J2); zonula occludens-1(ZO-1)