Shen-ling-bai-zhu-san, a spleen-tonifying Chinese herbal formula, alleviates lactose-induced chronic diarrhea in rats

Ethnopharmacological relevance: Shen-ling-bai-zhu-san (SLBZS) was firstly documented in ancient Chinese medical works "Tai Ping Hui Min He Ji Ju Fang" in Song-dynasty. It has been widely used for treating gastrointestinal disorders such as diarrhea with poor appetite for about 900 years. The present study is to observe the effects of SLBZS on high lactose diet-induced chronic diarrhea. Materials and Methods: Rats were subjected to a high lactose diet to induce chronic diarrhea, which were then administrated with SLBZS or smecta. General symptom, body weight, food consumption, water intake and fecal fluid content were recorded every day. The intestinal absorption function was determined by D-xylose uptake assay. The ultrastructures of intestine segments including jejunum, ileum, proximal and distal colon were observed by transmission electron microscopy. Additionally, sodium transport proteins including gamma-epithelial sodium channel (ENAC-gamma) and sodium/potassium-transporting ATPase subunit alpha-1 (ATP1A1) in distal colon were detected by immunohistochemistry and western blotting. Results: Diarrheal rats produced watery or loose, sticky feces, and presented inactiveness and grouping. A high lactose diet caused a significant decline in body weight, serum D-xylose level as well as food consumption rather than water intake. In contrast, general symptoms were improved to a certain extent and body weight loss was alleviated in the rats treated by SLBZS for one week. Fecal fluid content in diarrheal rats treated by SLBZS presented a gradual decrease trend with about 55% in the end, which was significantly less than the model group with about 81%. Meanwhile, SLBZS significantly improved the serum D-xylose level and reversed abnormal changes of tight junctions and microvilli in intestine. Additionally, SLBZS significantly modulated the abnormal expressions of ENAC-gamma and ATP1A1 in distal colon of diarrheal rats. Conclusions: These findings suggested that SLBZS exhibited ameliorating effects against lactose-induced diarrhea, which might be attributed to its modulations on intestinal absorption function as well as mucosal ultra structure.