Abstract: In order to investigate the effect of combined application of purslane and probiotics on prevention of heat-toxin syndrome diarrhea in mice, purslane and probiotics were used in this study. 144 male Kunming mice were randomly divided into 9 groups, namely: different dose of purslane (1, 2.5, 5.0 g·kg^-1 feed) groups, different doses of purslane (1, 2.5, 5.0 g·kg^-1 feed) and probiotics (2×10⁶ cfu·g^-1BW·d^-1) groups, probiotic (2×10⁶ cfu·g^-1BW·d^-1) group, model group and blank group. The model group and blank group mice were fed normal diet and blank group mice did not build model; Other mice were fed with medicated feed or/and intragastric probiotics. After 10 d treatment with drugs and/or probiotics, except blank group, the diarrhea model of the other group mice was constructed by gavage once a day with dried ginger extract for 10 days then intraperitoneal injection enterotoxigenic Escherichia coli(ETEC) for 3 days. The occurrence of diarrhea in mice was closely observed after attack bacteria. At the end of the experiment, blood samples were collected for biochemical examination, intestinal tissues were collected for histopathological examination and detection of inflammatory factors expression such as TNF-α、IL-1β、IL-6、IL-10、TGF-β1、IFN-γ. The results were as follow: (1) The diarrhea rate of mice in the model group was 87.5% and the diarrhea rate in the high dose purslane combined with probiotic group was just 12.5% at 24 h after attack bacteria. (2) Compared with the blank group, the mRNA expression of TNF-α, IL-1β, IL-10, IL-6, TGF-β1, IFN-γ were significantly increased in model group (P<0.05). Compared with the model group, the mRNA expression of the inflammatory factors mentioned above were significantly decreased (P<0.05) in the high dose purslane combined with probiotic group. (3) In the model group, the small intestine villi of mice were broken, partially necrotic and exfoliated, and the intestinal glands were deformed obviously. The intestinal villi of the high dose purslane combined with probiotics group were basically complete and the intestinal structure became normal. (4) Compared with the blank group, the content of Cl^- in serum of model group increased significantly (P<0.05), and the content of Ca²⁺ decreased significantly (P<0.05). Compared with the model group, the content of Cl^- in serum of the high dose purslane combined with probiotics group decreased significantly (P<0.05) and the content of Ca²⁺ increased significantly (P<0.05). The results showed that the high dose purslane combined with probiotics could effectively prevent the occurrence of diarrhea in mice induced by ETEC and dried ginger extract. Its mechanism included reducing intestinal inflammation by down-regulating the expression of gut associated inflammatory factors and restoring the electrolyte balance by regulating the blood Cl^- and Ca²⁺ levels.

Key words: combination of purslane and probiotics, enterotoxigenic Escherichia coli, mice, diarrhea model