Research on the function and mechanism of mannose-binding lectin regulating intestinal epithelial apoptosis / 局解手术学杂志

ABSTRACT

Objective To observe the effect of recombinant human mannose-binding lectin ( rhMBL) on apoptosis of intestinal epithelial cells. Methods Fourteen C57 mice were randomly divided into two groups. The LPS mice received intra-peritoneal injection of LPS for indu-cing acute intestinal barrier injury. The expression of MBL protein and mRNA were observed by immuno-histochemisty and RT-PCR respec-tively. The apoptosis of intestinal epithelial cells was detected by tunel staining. In vitro, the Caco-2 cells were treated with 0、 5、10、20 μg/mLrhMBL, flow cytometry was used to detect the apoptosis rate of Caco-2 cells. The Bax and Bcl-2 protein and mRNA were detected by Western blotting and Real-Time PCR methods between various groups. MAPK signal proteins were detected by Western blotting method. Results The MBL and TUNEL staining were apparently increased under LPS condition. The apoptotic rates of Caco-2 cells which were trea-ted by different rhMBL concentrations after 48 h were increased in 20μg/mL rhMBL when compared with other groups. The apoptotic rates of Caco-2 cells which were treated by 20 μg/mL rhMBL after different time were increased in time-dependent manner. The results of Western blotting and Real-Time PCR assay showed that levels of Bax/Bcl-2 was increased in Caco-2 cells which were treated by 20μg/mL rhMBL af-ter 48h. Meanwhile, the phosphorylation of P38 and ERK were obviously increased in Caco-2 cells. The inhibitory effect of ERK and P38 in-hibitors were studied by Western blotting. Our current study showed that a block in P38 MAPK dependent cell death might contribute to the decrease in 20μg/mL MBL-mediated Caco-2 apoptosis. Conclusion High concentration of rhMBL may play an important role in the intesti-nal epithelial cell apoptosis, and P38 pathway may be involved in this regulation.