Traditional Tibetan medicine Anzhijinhua San attenuates ovalbumin-induced diarrhea by regulating the serotonin signaling system in mice

Abstract Ethnopharmacological relevance Tibetan medicine has a history of 3800 years. Anzhijinhua San (AZJHS) which is a traditional Tibetan medicine was effective in the treatment of indigestion, anorexia and cold diarrhea etc. However, the effects of AZJHS on allergic diarrhea have not been reported. Aim of the study The aim of present study is to elucidate the effect of AZJHS on the preventive effect of experimental OVA-induced diarrhea and elucidate its possible anti- diarrhea mechanism. Materials and Methods Female BALB/c mice were sensitized with 50 μg Ovalbumin (OVA) and 1 mg alum by intraperitoneal injection twice during a 2-week period. From day 28, mice were orally challenged with OVA (50 mg) every other day, for a total of ten times. AZJHS (46.7, 467.0 mg/kg) were orally administered every other day from day 0 to 46. Severe symptoms of allergic diarrhea were observed. OVA-SIgE, 5-HT and its metabolites in serum were determined. Immunohistochemical and histopathology were performed in gastrointestinal tract tissues. 5-HT-related gene expression was assayed in colon. Results Severe symptoms of allergic diarrhea were observed in the model group. AZJHS (46.7, 467.0 mg/kg) ameliorated diarrhea and reduced anaphylaxis in mice. There was a very significant hyperplasia (P th challenged with OVA, and AZJHS (46.7, 467.0 mg/kg) significant suppressed the increases of 5-HT-related cells. The nuclei of EC cells of AZJHS (46.7, 467.0 mg/kg) group became bigger, and the secretory granules became smaller and fewer compare with the M group. AZJHS (46.7, 467.0 mg/kg) significant increased the relative fold changes of 5-HTP and 5-HT. The mRNA expression of serotonins transporter (Sert) and serotonin receptor 3 A (Htr3a) were significant decreased after the 10 th challenged with OVA and AZJHS (46.7, 467.0 mg/kg) increased them significantly. Conclusions Our results showed for the first time that AZJHS can attenuate Ovalbumin-induced diarrhea in mice by regulating 5-HT and its metabolites in serum, the number and morphology of 5-HT-related cells in gastrointestinal tract, and 5-HT-related gene expression in colon. The findings indicate that AZJHS may have a therapeutic application for allergic diarrhea.