Crocetin attenuates norepinephrine-induced cytotoxicity in primary cultured rat cardiac myocytes by antioxidant in vitro.

This study aims to investigate the protective role of crocetin, a natural antioxidant, against cytotoxicity produced by exposure to norepinephrine (NE) in primary cultured rat cardiac myocytes. Reactive oxygen species (ROS) and Ca(2+) in cells were evaluated by fluorescence microplate reader using 6-carboxy-2',7'-dichlorofluorescein and fluoro-3-acetoxymethyl ester, respectively. Lipid peroxidation was quantified using thiobarbituric acid-reactive substances. The activities of superoxide dismutase (SOD) and contents of glutathione (GSH) were detected by xanthine/xanthime oxidase-mediated ferricytochrome c reduction assay, and recycling effection of glutathione disulfide with GSH reductase and NADPH, respectively. The apoptotic cells were assayed by fluorescein diacetate (FDA)-ethidium bromide (EB) two-staining method. Intracellular accumulation of ROS, Ca(2+), and products of lipid peroxidation resulting from NE were significantly reduced by crocetin. Preincubation of primary cultured rat cardiac myocytes with crocetin remarkably prevented the decrease in SOD activity and quantities of GSH induced by NE. The percentage of NE-induced apoptosis in the cells was decreased by FDA-EB two-staining assay after pretreated with crocetin. The results showed that crocetin may ameliorate NE-induced injury in cardiac myocytes by enhanced SOD activity and increased quantities of GSH, decreased lipid peroxidation and Ca(2+) in cells, and apoptosis death ratio that may represent the cellular mechanisms for its cardioprotective role.