[Effect of Electroacupuncture Intervention on Gastrointestinal Motility and Expression of Insulin-like Growth Factor 1 and Its Receptor Proteins in Gastric Antrum in Diabetic Gastroparesis Rats].

OBJECTIVE: To observe the effect of electroacupuncture (EA) intervention of "Zusanli"(ST 36), etc. on gastrointestinal motility and levels of insulin-like growth factor 1 (IGF-1) and IGF-1 receptor (IGF-1 R) proteins in the gastric antrum in diabetic gastroparesis (DGP) rats, so as to study its mechanism underlying improvement of DGP.

METHODS: Fifty SD rats, half male and half female, were randomly allocated to control, model, EA acupoint, EA non-acupoint and medication (metoclopramide) groups ( n =10 rats/group). The DGP model was induced by 2% streptozotocin (STZ, i.p.i.,55 mg/kg) and high fat-sugar forage for 8 weeks. EA (10 Hz/50 Hz, 2 mA) was applied to "Zusanli"(ST 36), "Liangmen"(ST 21), "Sanyinjiao"(SP 6) and non-acupoints (about 5 mm lateral to ST 36, ST 21 and SP 6, respectively) for 20 min, one daily for 15 days, and 1.7% metocloppramide (1 mL/100 g) was given (gavage) to rats of the medication group, once daily for 15 days. After the treatment, the rats' general conditions were scored, the blood glucose level was determined using a glucometer, and the gastrointestinal mobility was evaluated by measuring the gastric emptying rate (GER) and the intestinal propulsion rates (IPR) marked by oral-infused phenol red solution (50 mg/dL). The immunoactivity levels of IGF-1 and IGF-1 R of gastric antrum tissue were detected by enzyme-linked immunosorbent assay (ELISA).

RESULTS: After modeling, the symptom integrative score, the blood glucose, IGF-1 and IGF-1 R levels were significantly increased ( P <0.01), and the GER and IPR were notably decreased relevant to the control group ( P <0.01). After EA stimulation of ST 36, ST 21 and SP 6, the symptom score, blood glucose, and IGF-1 and IGF-1 R levels of the gastric antrum were significantly reduced, while the GER and IPR were considerably increased ( P <0.05, P <0.01). Except the GER and IPR were considerably increased in the medication group( P <0.05, P <0.01), no significant changes were found in the symptom integrative score, the blood glucose, IGF-1 and IGF-1 R levels in both EA non-acupoint and medication groups relevant to the model group ( P >0.05),the GER and IPR in the EA non-acupoint group ( P >0.05). Compared with the EA acupoint group, the symptom integrative score, IGF-1 and IGF-1 R levels were significantly increased in both EA non-acupoint and medication groups( P <0.05, P <0.01).

CONCLUSIONS: EA stimulation can improve gastrointestinal motility and lower blood glucose in DGP rats, which may be closely associated with its effectiveness in reducing IGF-1 and IGF-1 R immunoactivity levels in gastric antrum.