Astaxanthin Protects Against H₂O₂- and Doxorubicin-Induced Cardiotoxicity in H9c2 Rat Myocardial Cells

Astaxanthin (AST) is a carotenoid that has positive effects on various organs and tissues. It also exhibits a cardioprotective action. In this study, the influence of AST on the survival of H9c2 cardiomyocytes under hydrogen peroxide (H₂O₂)- and doxorubicin (DOX)-induced cardiotoxicity was investigated. Under these conditions, the content of cytosolic Ca²⁺ was measured, and changes in the area of the mitochondrial mass, as well as in the content of the voltage-dependent anion channel 1 (VDAC1), the autophagy marker LC3A/B, and the pro-apoptotic transcription factor homologous protein (CHOP), were determined. It was found that AST removed the cytotoxic effect of H₂O₂ and DOX, while cell survival increased, and the mitochondrial mass did not differ from the control. At the same time, a decrease in the content of cytosolic Ca²⁺ and the restoration of the VDAC1 level to values close to the control were observed. The restoration of the CHOP level suggests a reduction in endoplasmic reticulum (ER) stress in cells. The results allow us to consider AST as a potential agent in the prevention and/or treatment of cardiac diseases associated with oxidative stress.