Abstract: 【Objective】 The purpose of this experiment was to study the protective effect of traditional Chinese medicine (TCM) combined with probiotics on E.coli diarrhea in mice.【Method】 The best factor ratio of TCM combined with probiotics was selected by orthogonal test. 60 mice were randomly divided into blank group, model group, TCM group, probiotics group and TCM combined probiotics group, with 12 mice in each group. Mice in blank group were intraperitoneally injected with normal saline (0.2 mL/mouse), model group, TCM group, probiotics group and TCM combined probiotics group were intraperitoneally injected with E.coli isolate 1×10⁷ CFU/kg. The TCM group was gavaged with mixed TCM solution for 10 mL/kg(the concentration of dandelion extract was 0.25 g/mL, and the concentration of total flavonoids of Astragalus membranaceus and Astragalus polysaccharides were 0.05 g/mL), the probiotic group was gavaged with Bacillus subtilis suspension for 4 mL/kg (Bacillus subtilis contents 5×10⁷ CFU/mL), the TCM combined with probiotics group was gavaged with the mixture of TCM and Bacillus subtilis, they were given by gavage once a day for 3 days. The diarrhea, body weight and dietary quantity of the mice were recorded every day. 12 hours after the last administration, the heart, liver, kidney, spleen and lung were separated, weighed and the viscera coefficient were calculated. Hematological indicators were analyzed by blood test. Fecal and small intestine contents were taken to observe fecal occult blood and count bacteria. The activity of MPO in serum and small intestine were detected by ELISA.【Result】 The best factor ratio of TCM combined with probiotics was A₁B₂C₂D₂. The results showed that compared with blank group, the diarrhea rate of the model group was 100% without self-healing and there were obvious symptoms and pathological changes. The diarrhea index was extremely significantly increased (P<0.01), body weight and dietary amount were extremely significantly decreased (P<0.01), liver and spleen indexes were increased (P<0.05), the lymphocyte ratio and intermediate cell ratio were decreased (P<0.05) and the granulocyte ratio were extremely significantly increased (P<0.01) in model group. Compared with model group, diarrhea index in TCM group and TCM combined with probiotics group was extremely significantly decreased (P<0.01), body weight and dietary quantity were increased (P<0.05), liver and spleen indexes in TCM group were decreased (P<0.05), viscera indexes in TCM combined with probiotics group were extremely significantly decreased (P<0.01). LYM was increased significantly (P<0.05) and GRAN was decreased significantly (P<0.05) in TCM group, probiotics group and TCM combined probiotics group. Hematological indexes were greatly improved (P<0.05). Fecal occult blood test results showed that model group was strong positive, TCM group and probiotics group were weak positive, while TCM combined with probiotics group was negative. Compared with blank group, the number of E.coli in intestine in model group was extremely significantly increased (P<0.01), and the activity of MPO was extremely significantly increased (P<0.01). Compared with model group, the number of E.coli in intestine and the activity of MPO in serum and small intestine of mice in TCM group and TCM combined probiotics group were significantly decreased (P<0.05).【Conclusion】 TCM combined with probiotics can reduce diarrhea index, liver and spleen indexes, increase body weight and diet, turn fecal occult blood into negative, and reduce the number of E.coli in intestine and the activity of MPO in serum and small intestine, so as to provide a synergistic protective effect on E.coli induced diarrhea in mice.

Key words: traditional Chinese medicine (TCM) combined with probiotics; bacterial diarrhea; mice; E.coli