LAUSR

The present study evaluated the cardioprotective effect of astaxanthin (ASX) against isoproterenol (ISO) induced myocardial infarction in rats via the pathway of mitochondrial biogenesis as the possible molecular target of astaxanthin. The control group was injected with normal physiological saline subcutaneously for 2 days. The second group was injected with ISO at a dose of 85 mg/kg bwt subcutaneously for 2 days. The third, fourth and fifth groups were supplemented with ASX at doses of 10, 20, 30 mg/kg bwt, respectively daily by oral gavage for 21 days then injected with ISO dose of 85 mg/kg bwt subcutaneously for 2 successive days. Isoproterenol administration in rats elevated the activities of Creatine kinase‐MB (CK‐MB), aspartate transaminase (AST), lactate dehydrogenase (LDH), and other serum cardiac biomarkers Troponin‐I activities, oxidative stress biomarkers, malondialdehyde(MDA), Nuclear factor‐kappa B (NF‐KB), while it decreased Peroxisome proliferator‐activated receptor‐gamma coactivator (PGC‐1α), Nuclear factor erythroid‐2‐related factor 2 (Nfe212), mitochondrial transcriptional factor A (mt TFA), mitochondrial DNA copy number and glutathione system parameters. However, Astaxanthin decreased the activities of serum AST, LDH, CK‐MB, and Troponin I that elevated by ISO. In addition, it increased glutathione peroxidase and reductase activities, total glutathione and reduced GSH content, and GSH/GSSG ratio, mtDNA copy number, PGC‐1α expression and Tfam expression that improved mitochondrial biogenesis while it decreased GSSG and MDA contents and NF‐KB level in the cardiac tissues. This study indicated that astaxanthin relieved isoproterenol induced myocardial infarction via scavenging free radicals and reducing oxidative damage and apoptosis in cardiac tissue.