Objective: To investigate the effect of electroacupuncture (EA) plus treadmill exercise on the expression of peroxisome proliferator activated receptor γ coactivator 1α(PGC-1α), Irisin, AMP-activated protein kinase (AMPK) in skeletal muscle of diet-induced obesity (DIO) rats, so as to explore its mechanism underlying body reduction promotion.
Methods: Forty-two male SD rats were divided into normal diet (control, n＝10), high fat diet (model), EA, treadmill exercise and EA plus treadmill exercise (combination) groups (n＝8 in each of the latter 4 groups). The obesity model was established by feeding the rats with high fat diet. EA (2 Hz/15 Hz, 1 mA) was applied to bilateral "Zusanli" (ST36) and "Tianshu" (ST25) for 30 min, 5 times per week for a total of 8 weeks. Rats of the treadmill exercise group were forced to perform exercise on a treadmill (16 m/min) for 30 min, 5 times per week for a total of 8 weeks. Rats in the combination group received the above-mentioned two methods. During the treatment, rats in the control group were fed with normal fodder, rats in other groups were fed with high fat fodder, and their body weight was measured once a week. The expression levels of PGC-1α， fibronectin type Ⅲ domain containing 5 (FNDC5), AMPK mRNA and protein of skeletal muscle were measured by quantitative real-time PCR and Western blot，respectively.
Results: After modeling, the body weight was significantly increased (P<0.05), and the expression levels of PGC-1α and FNDC5 mRNA and protein, AMPK mRNA and phosphorylated AMPK (p-AMPK) protein in the skeletal muscle were considerably decreased in the model group relevant to the control group (P<0.05). Following the treatment, the body weight was significantly down-regulated, while the expression levels of PGC-1α and FNDC5 mRNAs and proteins, AMPK mRNA and p-AMPK protein were obviously up-regulated in the EA, treadmill exercise and combination groups relevant to the model group (P<0.05). The therapeutic effect of EA plus treadmill exercise was significantly superior to those of both simple EA and simple treadmill exercise in down-regulating the body weight, as well as in up-regulating the expression of PGC-1α and FNDC5 mRNAs and proteins, AMPK mRNA, and p-AMPK protein (P<0.05).
Conclusion: Both EA and treadmill exercise can significantly increase the expression of PGC-1α， FNDC5 and p-AMPK in skeletal muscle of DIO rats, suggesting their efficacy in restoring fatty acid oxidation in skeletal muscle cells and improving mitochondrial function, which may contribute to their function in body reduction. The therapeutic effect of EA plus treadmill exercise is better than that of simple EA and simple treadmill exercise.
Keywords: AMP-activated protein kinase; Electroacupuncture; Exercise; Irisin; Obesity; PGC-1α.