Zhutong Decoction relieves constipation by enhancing intestinal peristalsis through modulation of C-KIT/ANO1 and PDGFRα/SK3 in the SIP syncytium.

Ethnopharmacological Relevance: Slow transit constipation (STC) is a common gastrointestinal disease. Zhutong Decoction (ZTD), a traditional empirical prescription, is composed of Zhizhu Decoction and Prunus persica (L.) Batsch. ZTD can strengthen the spleen by advancing Qi and promote defecation by moistening the intestine. ZTD is commonly employed clinically for the treatment of constipation caused by insufficient gastrointestinal peristalsis. However, the mechanisms of ZTD in treating constipation are still unknown.

Aim Of The Study: This study aimed to evaluate the therapeutic efficacy of ZTD in treating STC, and explore its pharmacodynamic substances and underlying mechanisms.

Materials And Methods: Therapeutic effect of ZTD in STC was evaluated using loperamide-induced STC rat model. Immunofluorescence, western blotting, and RT-qPCR were used to detect the expression of proteins and genes associated with the intestinal motility. Chromatography and mass spectrometry were utilized to identify the potential active components present in ZTD that are absorbed in the rat plasma and colon. Ex vivo intestine motility experiments were conducted to assess the pharmacodynamic substances and elucidate their mechanisms of action.

Results: ZTD significantly ameliorated constipation symptoms, including reduced fecal number, shorter stool length, and decreased gastrointestinal transit ratio. ZTD restored balance in the SIP syncytium, which is composed of smooth muscle cells (SMC), interstitial cells of Cajal (ICC), and platelet-derived growth factor receptor α positive cells (PDGFRα cells), by upregulating the expression of C-KIT/ANO1 and downregulating the expression of PDGFRα/SK3. Furthermore, ZTD increased SMC contractions in the SIP syncytium through the CAM/MLCK/CPI-17 pathway. In the duodenum, atractylenolide II and atractylenolide III induced contractions through ANO1 and SK3, whereas hesperidin, neohesperidin, and naringin induced contractions only through ANO1. In the colon, atractylenolide II, atractylenolide III, and nobiletin promoted contractions via both ANO1 and SK3.

Conclusions: ZTD ameliorated loperamide-induced STC in rats by promoting intestinal peristalsis, and the mechanisms related to enhanced SMC contractility involved restoring the balance between C-KIT/ANO1 and PDGFRα/SK3 in the SIP syncytium.