[Electroacupuncture promotes browning of white adipose tissue by regulating mTOR/SREBP1 signaling pathway in obese mice].

OBJECTIVE

To investigate the regulatory effect of electroacupuncture (EA) at "Zusanli" (ST36) and "Tianshu"(ST25) on the mammalian target of rapamycin (mTOR)/sterol regulatory element-binding protein 1 (SREBP1) signaling pathway in obese mice, and to analyze its mechanism in promoting the browning of white adipose tissue for the prevention and treatment of obesity.

METHODS

Among 38 male C57BL/6J mice of SPF grade, 8 mice were randomly selected as the normal group, and the remaining 30 mice were fed with high-fat diet to establish obesity model. Sixteen successfully modeled mice were randomly divided into a model group and an EA group, 8 mice in each group. In the EA group, EA was applied at bilateral "Zusanli" (ST36) and "Tianshu" (ST25), 30 min a time, once daily, 5 times a week, for 4 consecutive weeks. Body mass was measured before and after intervention, and Lee's index was calculated. After intervention, fasting blood glucose,insulin, and serum lipid profile indexes (total cholesterol [TC], triglyceride [TG], low-density lipoprotein cholesterol [LDL-C]and high-density lipoprotein cholesterol [HDL-C]) were detected by ELISA, and the insulin resistance index was calculated;abdominal adipose tissue mass was measured, and the morphology of abdominal adipose tissue was observed by HE staining;the mRNA expression of mTOR, SREBP1, peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α),uncoupling protein 1 (UCP1), PR domain-containing protein 16 (PRDM16) and cell death-inducing DNA fragmentation factor-α-like effector A (Cidea) in abdominal adipose tissue was detected by real-time fluorescent quantitative PCR, the protein expression of mTOR, SREBP1, PGC-1α, UCP1, PRDM16 and Cidea in abdominal adipose tissue was detected by Western blot.

RESULTS

Compared with the normal group, in the model group, the body mass and abdominal adipose tissue mass were increased (P<0.01); the Lee's index, fasting blood glucose, insulin level and insulin resistance index were increased (P<0.01); the serum levels of TC, TG and LDL-C were increased (P<0.01), and the serum HDL-C level was decreased (P<0.01); the adipocyte diameter in abdominal adipose tissue was enlarged; the mRNA and protein expression of mTOR and SREBP1 was increased (P<0.01), and the mRNA and protein expression of PGC-1α, UCP1, PRDM16 and Cidea in abdominal adipose tissue was decreased (P<0.01). Compared with the model group, in the EA group, the body mass and abdominal adipose tissue mass were reduced (P<0.01); the Lee's index, fasting blood glucose, insulin level and insulin resistance index were decreased (P<0.01); the serum levels of TC, TG and LDL-C were decreased (P<0.01), and the serum HDL-C level was increased (P<0.01); the adipocyte diameter in abdominal adipose tissue was reduced; the mRNA and protein expression of mTOR and SREBP1 was decreased (P<0.05), and the mRNA and protein expression of PGC-1α,UCP1, PRDM16 and Cidea in abdominal adipose tissue was increased (P<0.01).

CONCLUSION

EA at "Zusanli" (ST36) and"Tianshu" (ST25) can alleviate obesity and regulate glycolipid metabolic disorders in mice. The mechanism may be related to inhibiting the mTOR/SREBP1 signaling pathway, up-regulating the expression of PGC-1α, UCP1, PRDM16 and Cidea, and promoting the browning of white adipose tissue.