Effect of Electroacupuncture at Zusanli(ST36)on EC Cells and Visceral Sensitivity in Diarrhea-Predominant Irritable Bowel Syndrome Model Rats
Objective:To explore the effects of electroacupuncture stimulation at the Zusanli(ST36)point on EC cells,serotonin(5-HT),and tryptophan hydroxylase 1(TPH1)in diarrhea-predominant irritable bowel syndrome(IBS-D)model rats and analyze the underlying mechanisms.Methods:Eighteen adult male rats were randomly divided into a control group(6 rats)and a model group(12 rats).The IBS-D model was established in the model group using chronic restraint stress combined with castor oil gavage.After successful modeling,the 12 rats were randomly divided into a model group and an electroacupuncture group(6 rats each).The control and model groups did not receive electroacupuncture,while the electroacupuncture group received daily electroacupuncture at Zusanli point for 20 minutes each day for 7 days.We observed body weight gain,colonic rectal distension(CRD)and abdominal withdrawal reflex(AWR)scores,diarrhea index,EC cell numbers,5-HT levels,TPH1 mRNA expression,and TPH1 protein expression using immunohistochemistry,ELISA,PCR,and Western blot techniques,respectively.Results:Compared to the control group,the model group showed a significant decrease in body weight gain,an increase in the diarrhea index,a reduction in CRD volume threshold,and an increase in AWR scores.EC cell numbers,5-HT concentrations,and TPH1 mRNA levels were also elevated(P<0.01,P<0.05).Compared to the model group,the electroacupuncture group had a reduced diarrhea index,an increased CRD volume threshold,a decreased AWR score,and lower EC cell numbers,5-HT concentrations,and TPH1 mRNA(P<0.01,P<0.05).Conclusion:Electroacupuncture at the Zusanli(ST36)point can reduce visceral sensitivity in IBS-D rats and effectively alleviate diarrhea symptoms.The mechanism may involve modulation of EC cell numbers and TPH1 expression,leading to a decrease in 5-HT levels and subsequent regulation of visceral sensitivity in IBS-D rats.