Effects of Yiqi Huoxue Decoction on Post-Myocardial Infarction Cardiac Nerve Remodeling and Cardiomyocyte Hypertrophy in Rats

Myocardial infarction can lead to ventricular remodeling and arrhythmia, which is closely related to nerve remodeling. Our previous study found that Yiqi Huoxue decoction (YQHX) can improve ventricular remodeling and reduce myocardial damage. Therefore, in this study, we observed the effect of YQHX on cardiac neural remodeling and cardiomyocyte hypertrophy and its possible mechanism. This research is composed of two parts: animal and H9c2 cells experiments. The animal model of acute myocardial infarction was established by ligating the left anterior descending coronary artery in Sprague Dawley (SD) rats. H9c2 cells were placed in 94% N2, 5% CO2, and 1% O2 hypoxic environment for 12 hours to replicate the hypoglycemic hypoxia model. The experimental results showed that, compared with the MI group, YQHX can significantly improve heart function after myocardial infarction and reduce nerve remodeling and myocardial hypertrophy. Pathological structure observation demonstrated reducing myocardial tissue damage and decreasing of cell cross-sectional area, diameter, and circumference. The positive rate of TH declined apparently, and the sympathetic nerve density was lower than that of the MI group. After YQHX was given for 28 days, the proneural remodeling factors TH, NGF, and GAP43 in the marginal zone of infarction and stellate ganglion decreased obviously while the inhibitory nerve remodeling factor Sema-3A increased. The myocardial hypertrophic protein ANP and β-MHC were also significantly inhibited with p-ERK1/2 protein expression level prominently reduced. There was no difference between the YQHX group and the Meto group. After myocardial infarction, nerve remodeling was seen in the marginal area of infarction and stellate ganglion, and the neuropeptides released by which promoted myocardial hypertrophy. The mechanism may be related to the ERK1/2 signaling pathway. YQHX could regulate the ERK1/2 signaling pathway, inhibit the release of nerve remodeling factors and myocardial hypertrophy protein to reduce nerve remodeling, and relieve myocardial hypertrophy.