[Electroacupuncture improves inflammatory reaction and insulin sensitivity in insulin-resistant obese rats]

To observe the effect of electroacupuncture (EA) on inflammatory reaction and insulin sensitivity in insulin-resistant obese (OIR) rats.

Thirteen male Wistar rats were randomly selected as the control group and fed with common diet. The other 39 rats were fed with high-fat diet for 8 weeks to establish OIR model and then randomized into model, EA and sham EA groups. EA (2 Hz, 1 mA) was applied to unilateral "Zusanli" (ST36), "Fenglong" (ST40), "Zhongwan" (CV12) and "Guanyuan" (CV4) for 15 min, once every other day for 8 weeks, and sham EA was applied to unilateral 4 control spots about 5 mm lateral to the aforementioned 4 acupoints after shallowly inserting acupuncture needles, but without electric current output. After 8 weeks' intervention, the body weight was recorded and the glucose infusion rate (GIR) measured using hyperinsulinemic-euglycemic clamp technique. At the 6^th week of intervention, glucose contents of intraperitoneal glucose tolerance test (IPGTT) and intraperitoneal insulin tole-rance test (IPITT) were measured. The levels of serum insulin (INS) and inflammatory factors as C-reactive protein (CRP), IL-6 and TNF-α were measured by using ELISA at the end of the treatment. The expression levels of IL-6, TNF-α, monocyte chemoattractant protein-1(MCP-1), IL-10 and IL-1β proteins and mRNAs in the abdominal adipose tissues were detected by Western blot and quantitative real time-PCR, separately. The CD68 expression (displaying infiltration of macrophages) of adipose tissue was detected using immunohistochemistry.

After modeling, the contents of glucose of IPGTT at 30, 60 and 120 min and those of IPITT at 15, 30, 60 and 120 min, serum INS, CRP, IL-6 and TNF-α, as well as the expression levels of IL-6, TNF-α, IL-1β and MCP-1 proteins and mRNAs and CD68 protein were significantly increased (P<0.01, P<0.05), while the levels of GIR and IL-10 protein and mRNA were obviously decreased in the model group in comparison with those of the control group (P<0.01), suggesting an increase of inflammation and a decline of INS sensitivity. Following the interventions, the increased contents of glucose of IPGTT and IPITT, serum INS, CRP, IL-6 and TNF-α, expression levels of IL-6, TNF-α, IL-1β and MCP-1 proteins and mRNAs and CD68 protein, and the decreased levels of GIR and IL-10 protein and mRNA were evidently reversed in the EA group compared with the model group (P<0.01, P<0.05) rather than those in the sham EA group (P>0.05).

EA can reduce the level of inflammation and improve insulin sensitivity in OIR rats.