Effect of Tanshinone ⅡA injection on intestinal mucosal tight junction protein in severe rat septic models / 中国中西医结合急救杂志

ABSTRACT

Objective To discuss the influence of Tanshinone ⅡA on the tight junction protein of intestinal mucosal epithelial cells in rat severe septic models. Methods Seventy-five Sprague-Dawley (SD) rats were randomly divided into sham operation group, model group and Tanshinone ⅡA injection high (20 mg/kg), medium (10 mg/kg) and low (5 mg/kg) dose groups, each group 15 rats. Sepsis rat models were established by cecal ligation and puncture (CLP) method, in sham operation group, only switched abdominal surgery was performed without CLP. In Tanshinone ⅡA injection groups, different doses of Tanshinone ⅡA were injected intraperitoneally after modeling for 10 minutes and 6 hours; in sham operation and model groups, equal volume of normal saline was injected intraperitoneally at the same times as above. After operation, 3 L/kg of normal saline was injected into the caudal vein in all rats for fluid resuscitation.Twelve hours after operation, the rats were killed, the abdominal lymph nodes, liver, spleen and kidney tissues were taken for bacterial culture and calculating the rate of bacterial translocation; under microscope, the histopathological changes of ileum mucosal tissues were examined and Chiu scoring was carried out; TdT-mediated dUTP nick end labeling (TUNEL) was applied to detect the ileum mucosal epithelial cell apoptosis and calculating the index (AI);fluorescence immunoassay and Western Blot methods were used to measure the contents and protein expression levels of tight junction protein, junctional adhesion molecule-1 (JAM), Claudin-1, Zonula occludens-1 (ZO-1), Occludin, c-Fos and Tryptase. Results ① In bacterial cultures of abdominal lymph node, liver, spleen and kidney, the positive rate of mesenteric lymph node was the highest, followed by liver and spleen, mainly Escherichia coli, Proteus mirabilis, etc. The highest positive rate of bacterial culture was in model group (38.8%), followed by low dose of Tanshinone ⅡA injection group (35.0%), and the lowest was 16.6% in high dose Tanshinone ⅡA injection group, the differences being statistically significant in comparisons between any pair of groups (all P < 0.05). ② Pathological examination showed that the pathological changes of ileum mucosa were obvious and the Chiu score (4.17±0.98 vs. 0) and AI (11.70±2.87 vs. 2.17±0.80) in model group were significantly higher than those in sham group (all P < 0.05); with the increase of dosage of Tanshinone ⅡA injection, the pathological changes of rat ileum mucosa were improved gradually, the Chiu score and AI were decreased gradually, and the degrees of decrease in high dose Tanshinone ⅡA group were more significant than those in model group (Chiu score 1.12±0.79 vs. 4.17±0.98, AI 3.65±1.98 vs. 11.70±2.87, both P < 0.05).③ Immunofluorescence staining showed that the positive staining of protein JAM, ZO-1 and c-Fos were all green in color, Claudin-1, Occludin and Tryptase were all red in color, the localizations of all of them were in the cytoplasm, the protein expression of JAM, Claudin-1, ZO-1, Occludin from strong to weak in turn were Sham group, high, medium, low dose Tanshinone ⅡA group and model group, the expression of c-Fos, Tryptase from strong to weak in turn were model group, low, medium, high dose Tanshinone ⅡA group and Sham group. ④ Western Blot showed that the expressions of ileum tissue JAM, Claudin-1, ZO-1 and Occludin in model group were all significantly lower than those of the sham group, while the expressions of c-Fos, Tryptase were obviously higher than those of the sham group, with the increase of dosage of Tanshinone ⅡA, the expressions of JAM, Claudin-1, ZO-1 and Occludin were increased gradually and the protein expressions of c-Fos and Tryptase were gradually decreased, and the changes in high dosage group of Tanshinone ⅡA were more significant than those in low and moderate groups [JAM (gray value) 25.39±1.82 vs. 12.41±1.34, 19.45±1.66, Claudin-1 (gray value) 28.44±1.56 vs.17.26±1.46, 21.23±1.34, ZO-1 (gray value) 28.84±1.59 vs. 16.45±1.21, 24.22±1.46, Occludin (gray value) 25.49±1.63 vs. 13.34±1.45, 19.45±1.37, c-Fos (gray value)15.76±1.36 vs. 27.84±1.36, 21.22±1.73, Tryptase (gray value) 14.44±1.41 vs. 28.14±1.38, 22.32±1.57], all the above comparisons of different dosage groups were statistically significant (all P < 0.05). Conclusion Tanshinone ⅡA injection may improve intestinal wall structure and reduce bacterial translocation by improving the intestinal mucosal tight junction protein in sepsis model rats, and this effect is positively correlated to Tanshinone ⅡA dosage.