Abstract Body (Do not enter title and authors here): Background: Coronary microembolization (CME) commonly occurs during PCI in acute coronary syndrome, leading to myocardial damage. The purpose of this study is to explore the effects of CME on autophagy-related microRNAs and protein pathways, and to identify possible mechanisms of myocardial injury caused by CME.
Methods: This study randomly divided rats into 6 groups: sham and CME1h, 3h, 6h, 9h, 12h groups. A rat model of CME was established by injecting autologous microthrombi into the left ventricle. Echocardiography and HE staining were performed to evaluate myocardial infarct size in each group. The expression of microRNA-144-3p and microRNA-214-3p, LC3-II, p62/SQSTM1, phosphatase, and PTEN was detected.
Results: Compared with the sham group, LVEF and LVFS decreased,LVESD increased (P<0.05) in the CME3h, 6h, 9h, and 12h groups,the myocardial infarct area significantly increased in the CME6h group (P<0.05). The expression of microRNA-144-3p and microRNA-214-3p in myocardial tissue increased after CME, reaching a peak at 1h (P<0.05); LC3II decreased at CME1h (P<0.05) and significantly increased in the CME6h group (P<0.05). p62/SQSTM1 increased at CME1h (P<0.05) and then gradually decreased, while PTEN increased after CME3h (all P<0.05), with a peak at 6h.
Conclusion: Autophagy showed dynamic changes after CME, suggesting that enhanced autophagy aggravates myocardial damage after CME. Related microRNAs and PTEN are involved in the regulation of autophagy after CME.