Zhi Zhu Ma Ren pill relieves constipation in mice through endoplasmic reticulum stress-mediated apoptosis.

Purpose: This study explores the detailed effects and mechanisms of Zhi Zhu Ma Ren Pill (ZZMRP) on constipation.

Methods: Mouse constipation was induced by using loperamide (Lop). The effects and mechanisms of ZZMRP on constipation were addressed by various methods including charcoal meals, hematoxylin and eosin (H&E) staining, immunohistochemistry, enzyme-linked immunosorbent assay (ELISA), terminal deoxynucleotidyl transferase deoxyuridine triphosphate (dUTP) nick end labelling (TUNEL), transmission electron microscopy, and western blot experiments.

Results: Lop-treated mice exhibited delayed transit and reduced ink progradation rates after charcoal meal administration. H&E staining confirmed severe pathologic symptoms in these mice. Additionally, a decline in interstitial Cajal cells (ICCs) was observed in Lop-treated mice, accompanied by reduced concentrations of 5-hydroxytryptamine (5-HT), acetylcholinesterase (AchE), substance P (SP), and vasoactive intestinal peptide (VIP), coupled with an elevated concentration of nitric oxide synthase (NOS). However, ZZMRP treatment markedly ameliorated these changes. In addition, ZZMRP introduction significantly reversed the Lop-induced enhancement in apoptosis rate, endoplasmic reticulum (ER) stress, and levels of proapoptotic proteins and ER stress proteins, and the decrease in the expression of antiapoptotic proteins. These effects were further confirmed with the use of 4-phenylbutyrate (4-PBA), which also reversed the changes in apoptosis rate and protein levels.

Conclusion: ZZMRP alleviates constipation primarily through modulating ER stress-mediated apoptosis in Lop-treated mice, suggesting its use as a therapeutic agent for constipation.