Laxative effect of Wenyang Yiqi Decoction on loperamide-induced astriction model mice.

Background: Although a common disease, astriction is difficult to treat and severely affects quality of life. Wenyang Yiqi Decoction (WYD) is a kind of traditional Chinese medicine (TCM) that is used to treat astriction; however, the mechanism remains unclear. Therefore, this work assessed the laxative effect of WYD on loperamide-induced astriction (LIA) model mice.

Methods: We replicated a constipation model in mice and detected changes in fecal parameters such as feces quantity and water content, intestinal transit function, and histopathological changes in the constipated mice. After five days of WYD intervention, mouse tissues were taken out for detection. We also measured the levels of gastrin (Gas), substance P (SP), acetylcholinesterase (AChE), and vasoactive intestinal peptide (VIP) in the mice's serum. Additionally, we used quantitative real-time polymerase chain reaction (qRT-PCR) and Western Blot to detect c-Kit and stem cell factor (SCF), and examined the effects of WYD on the tight junction (TJ) proteins occludin (Ocln), zonula occludens-1 (ZO-1), and claudin-1 (Cldn-1) in the mice's intestines.

Results: Through histopathological changes, we observed less destruction of epithelial cells and greater integrity of goblet and epithelial cells in WYD-treated mice than in mice in the loperamide group. qRT-PCR and western blot analysis of c-Kit and SCF showed that WYD could boost the levels of c-Kit and SCF. The qRT-PCR and immunohistochemical (IHC) analyses of enteral tight occludin (Ocln), occludenas-1 (ZO-1), and cldin-1 (Cldn-1) showed that WYD could boost the level of ZO-1 and decrease the level of Cldn-1. The study also investigated the effect of WYD treatment on the enteral barrier function of astriction model mice and found that the TJ proteins (ZO-1, Cldn-1) in the colon of the astriction model mice had significant changes compared to the normal group, and WYD intervention was found to increase the expression of ZO-1, and decrease the expression of Cldn-1.

Conclusions: WYD alleviates LIA by regulating enteral hormones, boosting the number of interstitial cells of Cajal (ICCs), or adjusting enteral block action.