Objective: To investigate the effects of electroacupuncture (EA) on the expression of adenosine receptor (AR) in the white adipose tissue (WAT) of diet-induced obese (DIO) mice, so as to reveal a peripheral mechanism of EA underlying improvement of body weight.
Methods: Forty three-week-old C 57 BL/6 male mice were divided into normal diet group (n=12) and high fat diet group (n=28) randomly, and fed by normal diet and high fat diet for 12 weeks, respectively. In the high fat diet group, mice with body weight over 20% heavier than that of the normal diet group were considered as obese mice. The normal diet mice and the obese mice were divided into normal group (CD, n=5) and normal plus EA group (CD+EA, n=7), or obese group (HFD, n=6) and obese plus EA group (HFD+EA, n=12). The CD+EA group and the HFD+EA group were treated with EA at "Zusanli"(ST 36) and "Neiting"(ST 44, 2 Hz/15 Hz, 0.6-1.0 mA) for 20 min, 6 times a week for 4 weeks. Body weight, ratio of WAT/body weight were calculated, qPCR and Western blot were applied to detect mRNA and protein levels of adenosine receptors in the epididymal adipose tissue (Epi-WAT), respectively.
Results: Compared with the normal diet group, high fat diet significantly increased body weight in C 57 BL/6 mice after feeding for 12 weeks (P<0.01); 18 out of 28 mice in the high fat diet group were classified as obesity. After treatment, the body weight and the ratio of Epi-WAT/body weight of the HFD group were increased than those in the CD group (P<0.05), the change of body weight in the HFD group was bigger than that in the CD group (P<0.01). Compared with the HFD group, the body weight and the ratio of Epi-WAT/body weight of the HFD+EA group were decreased after EA (P<0.05), the change of body weight was also significantly increased (P<0.01). No significant differences were found among the four groups in the expression level of A1R mRNA (P>0.05). The expression of A3R mRNA in the HFD group was lower than that in the CD group (P<0.01), while the expressions of A2A R and A2BR proteins were decreased in the HFD group than in the CD group (P<0.01). In comparison with the HFD group, the expression levels of A2AR and A2BR mRNAs and proteins were significantly up-regulated in the HFD+EA group, respectively (P<0.05, P<0.01).
Conclusions: EA intervention is able to reduce the body weight of DIO mice, which Feb be associated with its effects in regulating the expression of A2AR and A2BR in WAT, suggesting a new mechanism of EA in accelerating peripheral WAT metabolism.