OBJECTIVETo detect the changes in intestinal mucosal permeation in rats with methotrexate-induced small intestinal damage and investigate the protective effects of Changyanqing decoction.

METHODSRat enteritis model was established by methotrexate (MTX) and sodium chloride. The rats were randomly divided into normal control group, model group, N-acetylcysteine (NAC) group and Changyanqing decoction group, and Changyanqing decoction (100 mg/kg) or saline was administered daily in the corresponding groups by gastric irrigation for 6 days. The disease activity index (DAI), colonic mucosal damage index (CMDI) and histological score (HS) of the rats were observed and evaluated. The levels of mRNA expressions of TNF-alpha and IL-1beta were detected by semi-quantitative RT-PCR. The expression of IL-10 was detected by enzyme linked immunosorbent assay, and IkappaB expression was determined with Western blotting.

RESULTSCompared with the normal control group, the model group showed significantly increased DAI, CMDI and HS. The DAI, CMDI, and HS in rats treated with Changyanqing decoction were significantly decreased in comparison with those in the model group (P<0.01). The expressions of TNF-alpha and IL-1beta were significantly higher in MTX-treated group than in the control group. The expression of TNF-alpha and IL-1beta mRNA in the Changyanqing group and NAC group were significantly lower, but IL-10 significantly higher than those of the MTX group. In MTX group, obvious NF-kappaB activation was observed, whose expression was significantly stronger in the cell nuclei, and the IkappaB in the cytoplasm was markedly degraded.

CONCLUSIONChangyanqing decoction offers protection on intestinal mucosa by inhibiting NF-kappaB activation to reduce TNF-alpha and IL-1beta mRNA expressions and increase IL-10 expression.