Preventive effect of interleukin-22 On epithelial barrier function of T84 cells under hypoxia and possible mechanism

Abstract

Objective To investigate the effect of interleukin-22 (IL-22) on intestinal barrier function of T84 cells under hypoxia and the molecular mechanism.Methods T84 cells were randomly divided into 3 groups:the normoxia group (Nx),the hypoxia group (Hx,2％ O2 for6 h) and hypoxia plus 100 μg/L rIL-22 group (Hx + rIL-22).Transepithelial electrical resistance (TER) was determined,and the protein and mRNA expression of IL-22 receptor A1 (IL-22RA1) was detected.zonula occludens-1 (ZO-1),Occludin,Claudin-1 and Claudin-4 expression was examined by using reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting.Results Both mRNA and protein expression levels of IL-22RA1 were significantly reduced by 30.0％ and 63.0％ respectively in Hx group as compared with Nx group (P ＜ 0.01).The TER value in Hx group was decreased by 54.7％ as compared with Nx group (P ＜ 0.01),which could be reversed through the pretreatment of rIL-22 (P ＜ 0.01).The expression levels of ZO-1,Occludin,Claudin-1 and Claudin-4 in Hx group were lower than in Nx group (P ＜0.01),but pretreatment with rIL-22 could attenulate the decreased expression of TJs under hypoxia (P ＜0.01).Conclusion After binding to its receptor complex,IL-22 could maintain the epithelial barrier function through regulating the expressionof TJs. Key words: Interleukin-22; Intestinal barrier function; Transepithelial electrical resistance; Tight junctions