Metabolic mechanism of neonatal rat cardiomyocyte injury and apoptosis induced by saturated fatty acids

AIM: To study the changes of fatty acid uptake and utilization during saturated fatty acid-induced cardiomyocyte apoptosis in neonatal rats. METHODS: We observed palmitate-inducing cell apoptosis using annexin V-FITC and PI double-stained flow cytometry, change of fatty acid transporter/CD36 (FAT/CD36) expression and distribution using Western blotting, and activity of carnitine palmityl transferase-1 (CPT-1) using liquid scintillation detecting system. RESULTS: Cardiomyocyte apoptosis rate was increased significantly after 16 h treatment of palmitate. FAT/CD36 protein content on membrane increased significantly after 4 h treatment, whereas its mRNA increased significantly after 8 h treatment. Following the time of treatment by prolonged palmitate, there was no significant change of FAT/CD36 protein content on the membrane, but there was a significant decline of CPT-1 activity and increase of cardiomyocyte apoptosis. CONCLUSION: Accumulation of long-chain fatty acids and its intermediate metabolite in cardiomyocytes due to the decline of oxidation activity may be one of the mechanisms for palmitate-induced cardiomyocyte injury and apoptosis.