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

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. 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. 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. 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. 观察电针足三里等穴对糖尿病胃轻瘫(DGP)大鼠胃肠运动及其起搏细胞[Cajal间质细胞(ICC)]超微结 构的影响, 探讨电针治疗DGP的机制。 将50只SD大鼠随机分为A组、B组、C组、D组和E组, 每组10只, A组 为空白对照组, B组、C组、D组和E组采用单次腹腔注射2%的链脲佐菌素(STZ), 并配合8星期高糖高脂饮食建立DGP 大鼠模型。B组为模型组, 不接受治疗; C组为电针穴位组, 采用电针足三里、梁门、三阴交治疗; D组为电针非穴 位组, 采用电针足三里、梁门、三阴交的对照点治疗; E组为胃复安组, 采用胃复安药液灌胃治疗。采用ONE TOUCH 血糖仪测血糖, 酚红灌胃法测胃排空率及小肠移行率, 透射电镜法检测胃窦ICC超微结构。 造模后, B组、C 组、D组和E组大鼠血糖值与A组比较, 差异均具有统计学意义(P<0.01); 治疗后, D组和E组大鼠血糖值与C组比较, 差异均具有统计学意义(P<0.05, P<0.01)。B组大鼠胃排空率与A组比较, 差异具有统计学意义 (P<0.01); C组大鼠 胃排空率与B组比较, 差异有统计学意义(P<0.05); B组、C组、D组和E组大鼠小肠移行率与A组比较, 差异均具有 统计学意义(P<0.01), C组大鼠小肠移行率与B组比较, 差异有统计学意义(P<0.01)。B组大鼠ICC超微结构与A组比 较, 细胞呈凋亡状态; C组大鼠ICC有完整的基膜, 胞浆中可见数目较多的线粒体、高尔基体及粗面内质网, 结构尚 清晰, 偶见线粒体肿胀, 与邻近平滑肌细胞间有缝隙连接存在; D组及E组与B组相比无明显差异。 电针足三 里等穴可调控DGP大鼠血糖, 促进胃肠运动, 其作用机制可能与修复受损ICC结构有关。