Abstract: 【Objective】 The aim of this experiment was to study the therapeutic effect of traditional Chinese medicine formulas on calf-derived Escherichia coli-caused diarrhoea in mice,and to provide a reference basis for the treatment of Escherichia coli-caused diarrhoea in calves with traditional Chinese medicine.【Method】 162 mice were randomly divided into 9 groups,blank group,model group,traditional Chinese medicine treatment groups 2 formulas (with 3 concentrations (1.5,1.0 and 0.5 g/mL) for each) and Western medicine treatment group,with 3 replicates in each group and 6 mice in each replicate.Except for blank group,the mice in each group were injected intraperitoneally with 0.5 mL Escherichia coli suspension with a concentration of 1×10⁸ CFU/mL,and after diarrhoea appeared in mice,the test mice in traditional Chinese medicine group were gave 0.2 mL extracts of traditional Chinese medicine formulas (Bai Tou Weng Tang plus or minus and Wu Mei San plus or minus),respectively,and the test mice in Western medicine group were gave 0.2 mL enrofloxacin.In model group,mice were fed 0.2 mL distilled water. The test lasted for 7 d.The body weight and food intake were recorded daily,and the diarrhoea index was counted on the 3rd day of treatment,mice were dissected on the 7th day of treatment,and pathological changes in the small intestine were detected,and the content of ileal mucosal immunoglobulins,sIgA and pIgR were detected using ELISA,and duodenal Claudin-1,Occludin and ZO-1 genes mRNA relative expression was detected using Real-time quantitative PCR.【Result】 Compared with model group,treatments with two herbal formulas could significantly increase the body weight and food intake of diarrhoeic mice,significantly reduce the diarrhoea index (P＜0.05),improve the pathological and histological lesions of the small intestine,and promote the repair of intestinal villi damage.Compared with model group,both formulas could significantly enhance the contents of mouse intestinal mucosal immunoglobulin sIgA and pIgR (P＜0.05),and significantly enhance the relative mRNA expression of mouse duodenal Claudin-1,Occludin and ZO-1 genes mRNA relative expression (P＜0.05).1.0 g/mL Wu Mei San plus or minus had the best therapeutic effect among the two traditional Chinese medicine formulas,and had no significant difference in intestinal histomorphology,intestinal mucosal immunoglobulin content and relative mRNA expression of tight junction proteins compared with Western medicine group.【Conclusion】 The addition and subtraction of Wu Mei San plus or minus and Bai Tou Weng Tang plus or minus could reduce the diarrhoea index and improve the pathological damage of the intestinal tract in mice,among which the therapeutic effect of the addition and subtraction of Wu Mei San plus or minus was more significant,and this study could provide reference for the treatment of diarrhoea of calves caused by Escherichia coli by traditional Chinese medicine.

Key words: Escherichia coli; mouse; traditional Chinese medicine; treatment; calf diarrhoea