Objective: To observe the effect of electroacupuncture (EA) on the activities of peroxisome proliferator-activated receptor gamma coactivator-1 alpha/uncoupling protein-1 (PGC-1 α/UCP-1) signaling pathway in white adipose tissue(WAT)of diet-induced obesity (DIO) rats, so as to reveal its underlying mechanism in body weight loss.
Methods: Thirty-four male Wistar rats were randomly divided into normal diet (control, n＝10), high fat diet (model), sham EA-acupoint and EA groups (n＝8 in each of the latter 3 groups). The obesity model was established by feeding the rats with high fat diet containing lard oil, sugar, albumen powder, cholesterol, salt and sodium cholate for 12 weeks. EA (2 Hz/15 Hz, 1 mA) was applied to bilateral "Zusanli" (ST 36) and "Tianshu" (ST 25) or sham acupoints (about 5 mm beside ST 36 and ST 25) for 30 min, once daily, 5 times per week for a total of 8 weeks. During the treatment, all rats were fed with normal diet, and their body weight and length were measured once a week for calculating the Lee's index. The contents of serum total cholesterol (TC) and triglyceride (TG) were measured by using biochemical methods. The immunoactivity of PGC-1 α and UCP-1 in the abdominal WAT was detected by immunohistochemistry.
Results: After modeling, the Lee's index, serum TC and TG contents were significantly increased, and the levels of serum HDL-C, and PGC-1 α and UCP-1 immunoactivity in WAT considerably decreased in the model group relevant to the control group (P<0.05). Following the treatment, the Lee's index, TC and TG contents were significantly down-regulated while HDL-C and PGC-1 α and UCP-1 immunoactivity were obviously up-regulated in the EA-acupoint group relevant to the model group (P<0.05).
Conclusion: EA can effectively reduce the body weight and adipose content in obesity rats, which may be closely related to its effect in up-regulating PGC-1 α/UCP-1 signaling in WAT, suggesting an efficacy of EA in promoting the browning of WAT.
Keywords: UCP-1; Electroacupuncture; Obesity; PGC-1 α; White adipose tissue.