[Effect of electroacupuncture at front-mu and back-shu points of large intestine on autophagy of Cajal interstitial cells in the colon of rats with slow transit constipation].

چکیده اصلی

OBJECTIVE: To explore the effect of electroacupuncture (EA) at front-mu and back-shu points of large intestine on autophagy of Cajal interstitial cells (ICCs) in the colon of rats with slow transit constipation (STC), and to analyze the mechanism of EA for mitigating STC. METHODS: Thirty-six SD rats were randomly divided into a blank group, a model group, an EA group, a mosapride group, an EA+rapamycin (RAPA) group and an EA+3-methyladenine (3-MA) group, with 6 rats in each group. The STC model was established by intragastric administration with loperamide hydrochloride. In the EA group, the EA+RAPA group and the EA+3-MA group, EA was operated at bilateral "Tianshu" (ST25) and "Dachangshu" (BL25), with dense-disperse waves (2 Hz/15 Hz in frequency), for 15 min each time. In the mosapride group, intragastric administration with mosapride solution was operated. In the EA+RAPA group and the EA+3-MA group, 30 min before acupuncture, the intraperitoneal injection was administered with RAPA and 3-MA solution, respectively. The intervention was delivered once daily and for consecutive 14 days in each group. After model establishment, the defecation time of the first red fecal particle was recorded in each group. After modeling and intervention, the number of fecal particles and fecal quality were recorded in each group over a 24-hour period. After intervention, the small intestinal propulsion rate was calculated in each group. HE staining was used to observe the histological morphology of colonic tissue, transmission electron microscopy was used to observe the ultrastructure of ICCs in the colon tissues, the immunofluorescence assay was used to observe the positive expression of the ICCs marker tyrosine kinase receptor (C-kit) in colonic tissue, the real-time quantitative PCR assay was used to detect C-kit mRNA expression, and Western-blot was used to detect C-kit and autophagy-related protein expression in each group. RESULTS: After modeling, compared with the blank group, the model group exhibited the prolonged defecation time of the first red fecal particle and the reduced number of fecal particles, and the decline of fecal quality and small intestinal propulsion rate (P<0.01). After intervention, compared with the model group, the EA group and the mosapride group showed the increase in the number of fecal particles, fecal quality, and small intestinal propulsion rate (P<0.01). Compared with the EA group, fecal quality and small intestinal propulsion rate were reduced in the EA+RAPA group (P<0.01). Compared with the blank group, the model group showed the impaired colonic mucosal structure and reduced goblet cell count; and autophagosomes and mitochondrial swelling were markedly observed in the cytoplasm of ICCs. The average fluorescence intensity of C-kit, the mRNA expression of C-kit, and the protein expression of C-kit and P62 all decreased, while the protein expression of LC3 and ATG5 increased in the model group (P<0.01). Compared with the model group, all other groups showed the improvements in colonic mucosal structure and ICCs ultrastructure, with the increase in average C-kit fluorescence intensity (P<0.01); the mRNA expression of C-kit and the protein expression of C-kit and P62 were elevated (P<0.01), while the protein expression LC3 and ATG5 were reduced in the EA group (P<0.01). When compared with the EA group, the protein expression of P62 decreased in the EA+3-MA group (P<0.01). CONCLUSION: Electroacupuncture at front-mu and back-shu point of large intestine can effectively alleviate intestinal motility disorder in rats with slow transit constipation, which may be related to inhibiting excessive autophagy of ICCs and repairing the structure and quantity of ICCs.

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