Clinical Value of lncRNA CASC19 in Myocardial Infarction and its Role in Myocardial Infarction-Induced Cardiomyocyte Apoptosis

To explore the effect of long non-coding RNA cancer susceptibility 19 (lncRNA CASC19) on the activity, apoptosis, and oxidative stress response of cardiomyocytes, so as to assess the clinical relevance and molecular mechanism of CASC19 in myocardial infarction (MI). CASC19 level was determined by using real-time quantitative polymerase chain reaction (RT-qPCR). MI model was constructed using hypoxia induction, and rat cardiomyocytes H9c2 were divided into control group, MI group, MI small interference negative control (MI-si-NC) group, MI-si-CASC19 group, MI-si-CASC19+microRNA-NC (miR-NC) group, and MI-si-CASC19+miR-218-5p inhibitor group. Tetramethylazolium salt colorimetric method and flow cytometry were used to evaluate cell activity and apoptotic capacity. Cellular oxidative stress was evaluated using malondialdehyde and superoxide dismutase kits. The relationship between CASC19 and miR-218-5p was confirmed by using dual-luciferase activity assay. CASC19 levels were enhanced in MI patients and hypoxia-induced cardiomyocytes. Downregulating CASC19 promoted the proliferation, while suppressed apoptosis and oxidative stress in the MI cell model. Moreover, low expression of miR-218-5p reversed the promotion of proliferation and inhibition of apoptosis and oxidative stress in MI cell models by silencing CASC19. Briefly, CASC19 may serve as a diagnostic marker for MI by sponging miR-218-5p to inhibit apoptosis and oxidative stress in cardiomyocytes and promote cell survival.