Docosahexaenoic acid protects against palmitate-induced mitochondrial dysfunction in diabetic cardiomyopathy.

• DHA alleviated PA-induced cytotoxicity in cardiomyoblast cells. • DHA ameliorated the progression of cardiomyopathy in a HFD-fed rat model of diabetes. • DHA improved palmitate-induced mitochondrial dysfunction both in vivo and in vitro. Regular consumption of n-3 polyunsaturated fatty acids is associated with decreased cardiovascular morbidity and mortality. This study assessed the therapeutic effect of docosahexaenoic acid (DHA) in palmitic acid (PA)-induced cytotoxicity in vitro and in rats fed a high-fat diet (HFD). H9C2 cells and rat primary cardiomyoblasts were exposed to PA or PA + DHA for 24 h. PA-induced lipotoxicity and mitochondrial dysfunction were evaluated by immunostaining, real-time PCR, cardiomyocyte contraction and transmission electron microscopy. The effects of dietary DHA on diabetic cardiomyopathy were evaluated in male Sprague-Dawley rats fed a reference diet rich in DHA, an HFD, or an HFD with added DHA for 16 weeks. Oxidative stress and lipotoxicity in rat heart tissue were assayed by Masson staining, immunohistochemistry, and TUNEL. In vitro studies showed that dietary DHA reduced the occurrence of cardiomyopathy and improved cardiac responses to PA. In the rat model, dietary DHA reduced mitochondrial oxidative stress in HFD-induced diabetic cardiomyopathy. Dietary DHA reduced mitochondrial oxidative stress and ameliorated PA-induced lipid toxicity. DHA consumption may have had direct effects on cardiovascular risk via myocardial protection. [ABSTRACT FROM AUTHOR]