Atractylodes Macrocephala Koidz. with Aucklandia Lappa Decne. Improves Diarrhea Symptoms in Irritable Bowel Syndrome of Spleen Deficiency with Diarrhea Rats by Regulating Autophagy in Cajal Interstitial Cells

OBJECTIVE To investigate the effects and mechanisms of Atractylodes macrocephala Koidz. with Aucklandia lappa Decne. on irritable bowel syndrome with diarrhea(IBS-D) with spleen deficiency type in rats.

METHODS Liquid chromatography mass spectrometry was used to detect the main components of decoction of Atractylodes macrocephala Koidz. with Aucklandia lappa Decne. SD rats were used as the study vehicle and randomly divided into control group, model group, positive control group and low-, medium-, high-dose of Atractylodes macrocephala Koidz. and Aucklandia lappa Decne. group(n=6). The rat model of spleen deficiency type IBS-D was established by intragastric administration of Cassia angustifolia Vahl combined with chronic stress method. The general conditions and weights of the rats in each group were recorded. Measured stool water content, intestinal transport rate, and visceral sensitivity by assessing the abdominal withdrawal reflex(AWR) threshold. Colonic tissue was collected from rats. The formation of autophagic vesicles in Cajal interstitial cells(ICC) was observed by transmission electron microscopy. Western blotting was used to detect the expression level of autophagy-related proteins. Immunofluorescence staining was performed to observe the level of ICC autophagy.

RESULTS Rats in the model group showed severe diarrheal symptoms, along with accelerated intestinal motility and increased intestinal sensitivity. Compared with the model group, treatment with Atractylodes macrocephala Koidz. and Aucklandia lappa Decne. improved the diarrheal symptoms, restored the body weight gain trend, and reduced fecal water content, intestinal transport rate, and visceral sensitivity in IBS-D rats with spleen deficiency syndrome. The number of autophagic vesicles formed in the ICC of colonic tissue in the treated rats was greater than that in the model group, and the expression levels of autophagy-related proteins were higher than those in the model group, while the expression levels of stem cell factor(SCF) and C-kitproto-oncogeneprotein(C-kit) were significantly lower than those in the model group. Moreover, the effects of Atractylodes macrocephala Koidz. and Aucklandia lappa Decne. on IBS-D rats were dose-dependent, and the effects of medium and high doses of Atractylodes macrocephala Koidz. and Aucklandia lappa Decne. were significant.

CONCLUSION Atractylodes macrocephala Koidz. and Aucklandia lappa Decne. reduce the intestinal transport rate and intestinal sensitivity of IBS-D rats by regulating autophagy of ICC, thereby alleviating diarrhea symptoms in IBS-D with spleen deficiency syndrome.