Abstract: ObjectiveTo investigate the protective effects of Astragalus injection (AI) on hydrogen peroxide (H₂O₂ ) induced injury in cardiomyocytes. MethodsCultured neonatal rat cardiomyocytes were divided into: control group; H₂O₂ group, in which cells were treated with H₂O₂ 0.15 mmol/L for 5 h; AI+H₂O₂ group, in which cells were pretreated with AI (with final concentration of 10, 30， 90 g/L) 30 min before H₂O₂ treatment; and AI (90 g/L)+L-NAME (20 μg/L). The cardiomyocyte viability was analysed by MTT assay, lactate dehydrogenase (LDH) activity and nitric oxide (NO) content were detected in culture media. Reactive oxygen species (ROS) were measured with laser-confocal-microscopy system. Mitochondrial memberane potential (ΔΨm) and apoptosis rate were measured with flowcytometry. ResultsCardiomyocyte viability in AI (10,30, 90 g/L) groups were higher than that in H₂O₂ group (P＜0.05). Compared with H₂O₂ group, LDH activity and ROS content in AI (90 g/L) group decreased (P＜0.01), NO content increased (P＜0.01), ΔΨm of cardiomyocytes increased (P＜0.05) and apoptosis rate decreased (P＜0.05). Compared with AI (90 g/L) group, after treatment combining with L-NAME, LDH activity and ROS content increased (P＜0.01), NO content decreased (P＜0.01), ΔΨm of cardiomyocytes decreased (P＜0.05) and apoptosis rate increased (P＜0.05). ConclusionAI can protect cardiomyocytes from H₂O₂ injury by increasing NO content and inhibiting cardiomyocyte apoptosis induced by ROS.

Key words: Astragalus injection, cardiomyocyte, reactive oxygen species, nitric oxide, apoptosis, oxidative stress, rat