Protective effect of heme oxygenase-1 on intestinal epithelial barrier function of Caco-2 cells under hypoxia

Abstract

Objective To investigate the regulator effect of heme oxygenase-1 (HO-1) on intestinal epithelial barrier function under hypoxia.Methods Eukaryotic overexpression vector pShuttle-CMVHO-1 was transfected into Caco-2 cells.The cells were divided into four groups:normoxia group,hypoxia group,transfection group,and negative control group.The mRNA and protein expression of HO-1 and Occludin was detected by using reverse transcription-polymerase chain reaction(RT-PCR) and Western blotting.Immunofluorescence was used to analyze Occludin.Results The expression levels of Occludin mRNA and protein were lower in hypoxia group than in normoxia group (0.43 ± 0.03 vs.1.0,P ＜ 0.01 ;0.62 ±0.07 vs.1.0,P ＜0.01).As compared with hypoxia group,the expression of Occludin mRNA and protein was significantly increased in transfection group (0.65 ±0.04 vs.0.43 ±0.03,P ＜0.05 ; 0.89 ± 0.06 vs.0.62 ±0.07,P ＜0.05).But there were no significant differences in the expression of Occludin mRNA and protein between the hypoxia group and negative control group (0.43 ± 0.03 vs.0.40 ± 0.05,P ＞0.05 ; 0.62 ±0.07 vs.0.61 ±0.04,P ＞0.05).Immunofluorescence staining showed that Occludin in linear fluorescence was distributed around the cell membrane in normoxia group,the immunofluorescence staining was disrupted in both hypoxia group and negative control group,and the immunofluorescence staining was not disrupted so seriously in transfection group.Conclusion HO-1 ameliorates intestinal epithelial dysfunction through up-regulating the expression of Occludin mRNA and protein under hypoxia. Key words: Heme oxygenase-1 ; Gene transfection; Tight junction; Intestinal mucosal barrier