Effect of electroacupuncture on myocardial electrical remodeling in rats with acute myocardial infarction.

Objectives: To investigate the mechanism of electroacupuncture (EA) at "Neiguan" (PC6) in impro-ving myocardial electrical remodeling in rats with acute myocardial infarction (AMI) by enhancing transient outward potassium current.

Methods: A total of 30 male SD rats were randomly divided into control, model and EA groups, with 10 rats in each group. The AMI model was established by subcutaneous injection with isoprenaline (ISO, 85 mg/kg). EA was applied to left PC6 for 20 min, once daily for 5 days. Electrocardiogram (ECG) was recorded after treatment. TTC staining was used to observe myocardial necrosis. HE staining was used to observe the pathological morphology of myocardial tissue and measure the cross-sectional area of myocardium. Potassium ion-related genes in myocardial tissue were detected by RNA sequencing. The mRNA and protein expressions of Kchip2 and Kv4.2 in myocardial tissue were detected by real-time fluorescence quantitative PCR and Western blot, respectively.

Results: Compared with the control group, cardiomyocyte cross-sectional area in the model group was significantly increased (<0.01), the ST segment was significantly elevated (<0.01), and QT, QTc, QTd and QTcd were all significantly increased (<0.05, <0.01). After EA treatment, cardiomyocyte cross-sectional area was significantly decreased (<0.01), the ST segment was significantly reduced (<0.01), and the QT, QTc, QTcd and QTd were significantly decreased (<0.01, <0.05). RNA sequencing results showed that a total of 20 potassium ion-related genes co-expressed by the 3 groups were identified. Among them, Kchip2 expression was up-regulated most notablely in the EA group. Compared with the control group, the mRNA and protein expressions of Kchip2 and Kv4.2 in the myocardial tissue of the model group were significantly decreased (<0.01, <0.05), while those were increased in the EA group (<0.01, <0.05).

Conclusions: EA may improve myocardial electrical remodeling in rats with myocardial infarction, which may be related to its functions in up-regulating the expressions of Kchip2 and Kv4.2.