Abstract
Heart failure (HF) is a serious threat to human health. Long noncoding RNAs (lncRNAs) are critical regulators of HF. The aim of the study was to investigate the molecular mechanism of MALAT1 in HF rats. MALAT1 expression was detected in serum of normal volunteers and HF patients, HF rats and isoproterenol (ISO)‑induced H9C2 cells, and its diagnostic value was evaluated in HF patients. Indexes related to cardiac functions and hemodynamics, myocardial injury, lipid metabolism, lipid oxidation, and inflammation were detected. Moreover, the downstream mechanism of MALAT1 was predicted and verified and in vivo experiments were further performed in ISO‑induced H9C2 cells to verify the effects of MALAT1 in HF. MALAT1 was highly expressed in serum of HF patients, HF rats and ISO‑induced H9C2 cells and was valuable in predicting HF. Inhibition of MALAT1 increased cardiac function and anti‑inflammation and alleviated myocardial injury, lipid metabolism, lipid oxidation and apoptosis rates. Inhibition of MALAT1 reduced H9C2 cell injury. MALAT1 competitively bound to microRNA (miR)‑532‑3p to upregulate LDLR protein. Inhibition of miR‑532‑3p weakened the protective effect of downregulated MALAT1 against H9C2 cell injury. We concluded that MALAT1 upregulated LDLR expression by competitively binding to miR‑532‑3p, thereby increasing pathological injury in HF.