Curcumin protects cardiac myocyte against hypoxia-induced apoptosis through upregulating miR-7a/b expression.

Objective: Curcumin has properties of anti-inflammation, anti-oxidation, anti-infection and anti-tumor, benefiting for the treatment of many diseases. The present study was aimed to investigate the role of curcumin in myocardial infarction (MI) and its potential mechanism involving transcription factor specific protein 1 (SP1).

Methods: After receiving curcumin, C57BL/6 mice subjected to left anterior descending (LAD) coronary artery occlusion to induce MI model. Infarct size was measured by triphenyl tetrazolium chloride staining. In vitro experiments, mouse cardiac myocytes (MCM) subjected to hypoxia after the incubation of curcumin, miR-7a/b and SP1 expression levels were detected by real-time PCR and western blot. Caspase-3 activity and TUNEL assay were performed to assess the cell apoptosis.

Results: In animal experiments, curcumin significantly reduced the infarct size compared with the control. It also up-regulated miR-7a/b expression and down-regulated SP1 expression. In hypoxia-induced MCM, curcumin led to the decrease of cell apoptosis. Transfected MCM with miR-7a/b inhibitor, curcumin induced the decrease of cell apoptosis and SP1 expression was reversed. Transfected with pcDNA-SP1, the decrease of cardiac myocytes apoptosis after the treatment of curcumin was also reversed.

Conclusion: Curcumin pre-treatment protected against hypoxia-induced cardiac myocytes apoptosis through the up-regulation of miR-7a/b and the down-regulation of SP1 expression.