Experimental study on the mechanism of low ⁃ frequency auricular electroacupuncture regulating gastric motility and comorbid depression in diabetic gastroparesis rats
Objective:The current study aims to observe the effects of auricular electroacupuncture on behavior,gastric emptying rate,expression of tyrosine kinase receptor(c-Kit)and corticotropin releasing factor(CRF)in gastric sinus tissues of rats with diabetic gastroparesis,and to investigate the mechanism of auricular electroacupuncture to improve gastric emptying and depression-like behavior in diabetic gastroparesis rats. Methods:Thirty-six SPF-grade SD rats were randomly divided into the control group,the model group,the auricular electroacupuncture group and the sham auricular acupuncture group,with 9 rats in each group. The control group was intraperitoneally injected with sodium citrate buffer solution,and the other three groups were intraperitoneally injected with streptozotocin(STZ)solution. After six weeks of treatment,the rats in the auricular electroacupuncture group were given electro -acupuncture at bilateral auricular point“stomach”once a day,five days a week for two weeks. The earlobe of the sham auricular acupuncture group was needled without electricity. After the treatment,the behavioral and gastric emptying rates were measured,and the protein and mRNA levels of CRF and c-Kit were respectively detected by ELISA and qRT-PCR in gastric sinus tissue. Results:In the open field test,the entries into the central area(CE),the percentage of time entering the central area(CT%)and the percentage of distance entering the central area(CD%)were significantly lower in the model group compared with the control group(all P < 0.05). CE,CT% and CD% were significantly higher in the auricular electroacupuncture group compared with the model group(all P < 0.05). In the forced swimming test,the percentage of floating time(FT%)was significantly higher in the model group compared with the control group(P < 0.05),and FT% were significantly lower in the auricular electroacupuncture group compared with the model group (P < 0.05). Compared with the control group,the gastric emptying rate of rats in the model group was significantly lower,and the mRNA and protein expression levels of CRF in the gastric sinus were significantly higher(P < 0.05),and the mRNA and protein expression levels of c -Kit were significantly lower(P < 0.05). Compared with the model group and the sham auricular acupuncture group,the gastric emptying rate of rats in the auricular acupuncture group was significantly higher,and the mRNA and protein expression levels of CRF in the gastric sinus were significantly lower(P < 0.05),and the mRNA and protein expression levels of c-Kit were significantly higher(P < 0.05). Conclusion:Low-frequency auricular electroacupuncture can improve gastric motility and depression-like behavior in diabetic gastroparesis rats,and its mechanism may be related to regulating the expression of related factors in gastric antrum tissue.