The objective of this study was to investigate the effect of astaxanthin on isoproterenol (ISO)-induced myocardial infarction and cardiac hypertrophy in rats. To evaluate the effect of astaxanthin on ISO-induced cardiac dysfunction, 18 aged Long Evans male rats were evenly divided into three groups. Group I (Control group) was given only the laboratory-ground food and normal water. Group II (ISO group) was administered ISO at a dose of 50 mg/kg subcutaneously (SC) twice a week for two weeks. Group III (Astaxanthin + ISO group) was treated with astaxanthin (25 mg/kg) orally every day and ISO 50 mg/kg SC twice a week for two weeks. ISO administration in rats increased the heart and left ventricular wet weights and increased inflammatory cell infiltration and fibrosis. Moreover, ISO administration increased the lipid peroxidation and decreased antioxidant enzyme activities in heart tissues. Astaxanthin treatment prevented the increased wet weight of heart and decreased inflammatory cell infiltration and fibrosis. The protective effect of astaxanthin was associated with reduction of free radicals by improving antioxidant enzyme function, as well as normalization and/or suppression of elevated oxidative stress markers, such as malondialdehyde (MDA), nitric oxide (NO), and advanced protein oxidation product (APOP) in ISO-administered rats. Furthermore, astaxanthin decreased the elevated activities of aspartate transaminase (AST), alanine transaminase (ALT), and creatinin kinase muscle/brain (CK-MB) in ISO-administered rats. In conclusion, astaxanthin may protect cardiac tissues in ISO-administered rats through suppression of oxidative stress and enhancement of antioxidant enzyme functions.
Keywords: antioxidant enzymes; astaxanthin; free radicals; heart, fibrosis; oxidative stress.