温阳益气方通过GAS/CCKBR抑制肠道NHE3活性调节钠吸收治疗慢传输型便秘的作用机制OA

Objective To explore the effects of Wenyang Yiqi Formula(温阳益气方,WYF)on gastrin(GAS)/cholecystokinin B receptor(CCKBR)and sodium-hydrogen exchanger 3(Na+/H+exchanger3,NHE3)and to investigate the mechanism of WYF in the treatment of slow transit constipation(STC).Methods The STC rat model and Caco-2 cells were used as in vivo and in vitro models,respectively.Various parameters including intestinal transit rate(ITR),colon tissue pathology,fecal characteristics and stool amount were assessed to evaluate the efficacy of WYF.Furthermore,cell viability,Na+/H+exchanger 3(NHE3)activity and expression,as well as gastrin and cholecystokinin B receptor(CCKBR)levels,were evaluated.The expressions of key proteins in the PI3K/PLC/PKC pathway was also measured,and a rescue experiment using a PI3K inhibitor was performed.Results Com-pared with normal controls,STC rats exhibited a reduced intestinal transit rate(ITR),decreased fecal output with drier stools,and aggravated colonic histopathological injury;these changes were alleviated by WYF.In vitro,WYF-medicated serum suppressed NHE3 activity and protein expression in Caco-2 cells in a dose-dependent manner,and a higher concentration reduced cell via-bility at 24-72 h.Mechanistically,gastrin(GAS)upregulated CCKBR and activated PI3K/PLC/PKC-related signaling while inhibiting NHE3 activity.The PI3K inhibitor LY294002 suppressed these signaling readouts and increased NHE3 activity,whereas WYF partially counteracted the effects of LY294002 and reduced NHE3 activity.CCKBR knockdown increased NHE3 activity,and the addition of GAS subsequently suppressed NHE3 activity,suggesting that the GAS/CCKBR axis participates in regulating NHE3.Conclusion WYF may alleviate STC phenotypes by modulating the GAS-CCKBR axis and its downstream PI3K/PLC/PKC-dependent signaling,thereby suppressing epithelial NHE3 expression,reducing NHE3-mediated Na+/H+exchange and Na+absorption,increasing luminal water content,and improving defecation.Causality warrants further confirmation using ion-flux assays and specific blockade experiments.