Study On Mechanism Of Action Of Chinese Herbal Medicine On Escherichia Coli-induced Diarrhea Of Piglet

In this paper, the mechanism of action of the five Chinese herbal medicines which are Isatis leaf, Isatis root, Forsythia fruit, Patrinia and Berberine hydrochloride, and their complex prescriptions on Escherichia coli-induced diarrhea of piglet, were systematically studied from five aspects which are the bacteriostatic activity in vitro on E.coli.,the antagonism against liquid retention mediated by Escherichia coli heat-labile enterotoxin ( LT ) , the antagonistic effect on diarrhea induced by castor oil in mice , the inhibiting action on increase of capillary permeability induced by acetic acid in mouse's abdominal cavity, the inhibiting effect on intestinal movement forward in mice ; The best complex prescription with all good activity against bacteria, antagonism against enterotoxin, anti-inflammatory action and antidiarrhea action was screened out. so these can provide theoretic bases for the selection of effective medicine to treat Escherichia coli-induced diarrhea of piglet and the development of the complex prescription composed of Chinese herbal medicine and antibacterial agents.The results of the bacteriostatic experiment in vitro indicated that out of five single medicines, except Berberine hydrochloride, Isatis leaf, Isatis root, Forsythia fruit and Patrinia, had obvious bacteriostasis .The bacteriostasis of Isatis root in vitro was the best and reached 0.0016g/ml (MIC) and 0.003 Ig/ml (MBC) respectively. Among the complex prescriptions, the bacteriostasis of Complex prescription composed of Isatis root, Forsythia fruit and Patrinia was as good as that composed of Isatis leaf, Isatis root and Forsythia fruit, and the vitro activity of these two complex prescriptions were stranger than Complex prescription composed of Forsythia fruit and Patrinia. The vitro activity of Complex prescription composed of Isatis root, Forsythia fruit, Patrinia and Berberine hydrochloride was poor.Escherichia coli was cultured in bacterial culture medium to which the extracts of the Chinese herbal medicines were added, and the cultural product LT was used to do experiment in ligated rabbit ileum. Isatis leaf, Isatis root and Forsythia fruit significantly or high significantly reduced the liquid retention caused by cultural supernatant fluid in ligated loops (P < 0.05, P < 0.05, P < 0.01). Antagonistic effects of Complex prescription composed of Isatis root, Forsythia fruit and Patrinia and Complex prescription composed of Isatis root, Forsythia fruit , Patrinia and Berberine hydrochloride on liquid retention LT-mediated in ligated loops were high significantly better than Complex prescription composed of Forsythiafruit and Patrinia and Complex prescription composed of Forsythia fruit, Patrinia and Berberine hydrochloride (P< 0.01, P< 0.01). Extracts of the Chinese herbal medicines and LT were directly injected into ligated loops together, the results of the effects on liquid retention LT-mediated in ligated loops showed that Patrinia could significantly reduce the liquid retention (P < 0.05), and Isatis leaf, Isatis root, Forsythia fruit didn't reach significant level. The inhibiting actions of Complex prescription composed of Isatis root, Forsythia fruit and Patrinia and Complex prescription composed of Isatis root, Forsythia fruit , Patrinia and Berberine hydrochloride on liquid retention in ligated loops were stranger than others. Isatis root, Forsythia fruit , Patrinia and Berberine hydrochloride had cooperation in antagonizing against enterotoxin, and yet Isatis leaf and other several medicines were antagonistic, so they were unsuitable to compatibility of medicines.The results of the experiment in diarrhea induced by castor oil in mice showed that within l-3h, when compared with the control, Complex prescription composed of Isatis root, Forsythia fruit and Patrinia had high significantly reduced frequency of diarrhea in mice (P < 0.01), and were also better than Isatis root, Forsythia fruit and Berberine hydrochloride (P < 0.05, P < 0.05, P < 0.05). At the same time , Incidence of diarrhea in mice of C...