Effect of electroacupuncture on calcium-activated chloride channel currents in interstitial cells of Cajal in rats with diabetic gastroparesis

To investigate the mechanisms of electroacupuncture (EA) at Zusanli (ST 36), Liangmen (ST 21) and Sanyinjiao (SP 6) in intervening diabetic gastroparesis (DGP) based on calcium-activated chloride channel. Forty Sprague-Dawley rats were randomly divided into four groups, including a normal control group (group A), a model group (group B), an EA group (group C) and a metoclopramide group (group D), with 10 rats in each group. A single intraperitoneal injection of 2% streptozotocin (STZ) combined with 8-week high-glucose high-fat diet was used to establish a DGP rat model. After intervention, gastrointestinal propulsive rate was observed; the expression level of transmembrane protein 16A (TMEM16A) was examined by immunohistochemistry; the Ca2+ concentration in interstitial cells of Cajal (ICCs) was detected by immunofluorescence; and whole-cell patch-clamp technique was applied to detect the current intensity of calcium-activated chloride channel (ICaCC) in ICCs in gastric antrum. After modeling, the blood glucose levels in group B, group C and group D were significantly increased compared with group A (all P<0.01); after intervention, compared with group B, the blood glucose levels in group C and group D were significantly decreased (P<0.05, P<0.01); the intra-group comparison of blood glucose level between after modeling and after intervention found significant difference only in group C (P<0.01). The gastrointestinal propulsive rates in group B, group C and group D were significantly different from that in group A (P<0.01 or P<0.05); the gastrointestinal propulsive rates were markedly higher in group C and group D than in group B (P<0.01, P<0.01). The expressions of TMEM16A in group B and group C were decreased compared with group A (P<0.01, P<0.05); the expressions of TMEM16A in group C and group D were increased compared with group B (P<0.01, P<0.05). The fluorescence intensity of Ca2+ was significantly lower in group B than in group A (P<0.01); the fluorescence intensity of Ca2+ was significantly higher in group C and group D than in group B (P<0.01, P<0.05). ICaCC in ICCs in group B was significantly decreased compared with group A; ICaCC in group C and group D were increased compared with group B. EA at Zusanli (ST 36), Liangmen (ST 21) and Sanyinjiao (SP 6) can significantly improve gastrointestinal motility in DGP rats by up-regulating the ICaCC in ICCs.