OBJECTIVE To observe the effect of electroacupuncture (EA) preconditioning at Tianshu (ST25) and Neiguan (PC6) on cardiac function and UCP1/BMP3b signaling pathway in brown adipose tissue (BAT) in mice with acute myocardial infarction (AMI), so as to explore the potential mechanism of EA at different acupoints in improving myocardial infarction.

METHODS Healthy adult mice and BAT excision mice were selected as the research objects, and they were divided into sham operation group, model group, PC6 group, and ST25 group. After one week of adaptive feeding, the mice in the intervention group were pretreated with bilateral EA at PC6 or ST25 for 20 minutes, respectively, and the AMI model was established by ligating the left anterior descending branch of the coronary artery. In the BAT resection group, BAT resection of the scapular region was performed before EA, and the rest of the intervention remained the same as before. Echocardiography was used to detect the changes in cardiac function. TTC staining was used to observe the myocardial infarct size. ELISA was used to detect the serum levels of cTnT and BMP3b in each group. The qPCR was used to detect the relative expression of β3-AR, UCP1 and BMP3b mRNA in mouse BAT. The protein expression of BMP3b in BAT and p-Smad1/5 in the heart were detected by Western blot.

RESULTS Compared with the sham operation group, the left ventricular EF and FS of the model group mice were decreased (P<0.001), the white infarct area was increased (P<0.001), the cTnT level in serum was increased (P<0.001), the mRNA expression levels of β3-AR, UCP1, and BMP3b in BAT were increased (P<0.05, P<0.01), and the protein expression of BMP3b was increased (P<0.01). The BMP3b content in serum was increased (P<0.001), and the protein expression of p-Smad1/5 in the heart was increased (P<0.01). Compared with the model group, the left ventricular EF and FS of mice in the ST25 and PC6 group were increased (P<0.001), the area of white infarction was reduced (P<0.001), and the cTnT level in serum was decreased (P<0.05, P<0.01). The mRNA contents of β3-AR, UCP1, and BMP3b in BAT of the ST25 group were significantly increased (P<0.05, P<0.01, P<0.001), the protein expression of BMP3b was increased (P<0.01), and the protein expression of p-Smad1/5 in the heart was increased (P<0.01), while there was no significant change in the PC6 group. After BAT resection, compared with the model group, the left ventricular EF and FS of the mice in the PC6 group were increased (P<0.001), the area of white infarction was reduced (P<0.001), and the cTnT in serum was decreased (P<0.001), while there was no significant change in the ST25 group; there was no significant change in the protein expression of p-Smad1/5 in the heart and the BMP3b content in the serum of the PC6 and ST25 groups.

CONCLUSION EA pretreatment at either ST25 or PC6 acupoints can produce myocardial protective effects. The protective effect of ST25 may be through influencing the UCP1/BMP3b signaling pathway in BAT, while PC6 does not depend on this pathway.