Study on the mechanisms of electroacupuncture for promoting gastrointestinal motility in rats with diabetic gastroparesis

Objective: To observe the effect of electroacupuncture (EA) at Zusanli (ST 36) on the gastrointestinal motility and the ultrastructures of pacemaker cells [the interstitial cells of Cajal (ICC)] in diabetic gastroparesis (DGP) rats and explore the mechanism of EA for DGP. Methods: A total of 50 Sprague-Dawley (SD) rats were randomly divided into group A, group B, group C, group D and group E, with 10 rats in each group. Group A was the blank control; a single intraperitoneal injection of 2% streptozotocin (STZ) was performed in rats of group B, group C, group D and group E, with high glucose and high fat diet for 8 weeks to establish the DGP rat models. Group B was the model group and the rats did not receive any treatment; group C was EA at acupoint group and the rats received EA at Zusanli (ST 36), Liangmen (ST 21) and Sanyinjiao (SP 6); group D was EA at non-acupoint group and the rats received EA at the control points of Zusanli (ST 36), Liangmen (ST 21) and Sanyinjiao (SP 6); group E was metoclopramide group and the rats were treated by intragastric administration of metoclopramide. Blood glucose was detected using ONE TOUCH blood glucose meter; gastric emptying rate and small intestine migration rate were measured using intragastric phenol red; ultrastructures of gastric antrum ICC were detected by transmission electron microscopy. Results: The differences of blood glucose between group B, group C, group D, group E versus that of group A were statistically significant after modeling (P<0.01); after treatment, the differences of blood glucose between group D, group E versus that of group C were statistically significant (P<0.05, P<0.01); the gastric emptying rate of rats in group B was statistically significant different from that in group A (P<0.01); the gastric emptying rate of rats in group C was statistically significant different from that in group B (P<0.01). The migration rates of rats’ small intestines in group B, group C, group D and group E were all statistically significant different from that in group A (P<0.01); the migration rate of rats’ small intestines in group C was statistically significant different from that in group B (P<0.01). The ultrastructure of rat’s ICC in group B showed apoptosis compared with that in group A; rat‘s ICC in group C had complete basement membrane, more cytoplasm mitochondria, Golgi and rough endoplasmic reticulum, showing clear structure, occasional mitochondria swelling and gap junctions with adjacent smooth muscle cells; there were no significant differences between group D, group E versus group B. Conclusion: EA at Zusanli (ST 36) plus other acupoints can regulate the blood glucose and promote gastrointestinal motility in DGP rats, and the mechanism may be related to repairing the damaged ICC structure. © 2017, Shanghai Research Institute of Acupuncture and Meridian and Springer-Verlag GmbH Germany.