[Electroacupuncture improves learning-memory ability in diabetic rats with cognitive impairment via inhabitating proinflammatory cytokine production through p38 MAPK and STAT3 pathway].

OBJECTIVE To investigate the effect of electroacupuncture (EA) on the p38 mitogen-activated protein kinase (p38 MAPK) and signal transducer and activator of transcription 3 (STAT3) pathway in hippocampus and frontal cortex of diabetic rats with cognitive impairment (CI), as well as the mechanism of EA in protection against CI in diabetic rats. METHODS Thirty SD rats were divided into normal, model and EA groups (n=10 rats/group). The diabetic model was established by i.p.injection of Streptozotocin solution(25 mg/kg), followed by high-fat diet raising for 1 month, and the CI rats was confirmed by Morris water maze tasks. The rats in the EA group were given acupuncture at "Zusanli" (ST36) "Neiting" (ST44) and "Yishu" (EX-B3) 20 min/d, among which ST36 and ST44 were treated with EA. The treatment was conducted 6 times a week for 4 weeks. The fasting blood glucose (FBG) contents were assayed by glucometer before and after treatment. The rats' learning-memory ability was detected by Morris water maze tasks. The expression levels of IL-6、IL-1β、TNF-α、p38 MAPK、p-p38 MAPK、STAT3 and p-STAT3 in hippocampus and frontal cortex were detected by Western blot and quantitative real-time PCR, separately. The mean fluorescence intensity of p38 MAPK and STAT3 was observed by immunofluorescence histochemistry. RESULTS After modeling, FBG and the escape latency of Morris water maze tasks were significantly increased in the model group compared with the normal group (P<0.001, P<0.01). Following EA treatment, the increased FBG and average escape latency were markedly reversed in the EA group relevant to the model group (P<0.05). Compared with the normal group, the proteins and mRNAs expression of IL-6, IL-1β, TNF-α, p38 MAPK, p-p38 MAPK, STAT3 and p-STAT3 in hippocampus and frontal cortex were significantly increased in the model group (P<0.001), as well as the mean fluorescence intensity of p38 MAPK and STAT3 in hippocampus and frontal cortex (P<0.001). Following EA intervention, the proteins and mRNAs expression of IL-6, IL-1β, TNF-α, p38 MAPK, p-p38 MAPK, STAT3 and p-STAT3, and the mean fluorescence intensity of p38 MAPK and STAT3 in hippocampus and frontal cortex were down-regulated(P<0.001, P<0.05). CONCLUSION EA can inhibit the over production of pro-inflammatory cytokines in diabetic rats with CI, possibly by regulating the expression of p38 MAPK and STAT3 pathway.