Abstract: Objective To explore the protective effect of shikonin on H9c2 cardiomyocytes damaged by hypoxia-reoxygenation(H/R). Methods H9c2 cells were divided into control group, H/R group, shikonin (0.1, 1 and 10 μmol/L) group, including 3 parallel wells in each group; MTT assay was used to detect the toxicity of shikonin on H9c2 cells; Apoptosis and cell cycle were detected by flow cytometry; DCFH-DA was used to detect the level of reactive oxygen species; biochemical detection of MDA and 8-OHdG in cells And GSH content; qPCR was used to detect the expression of γ-GCS, HO-1 and NQO1 mRNA; Western blot was used to detect the expression of Bax, Bcl-2, caspase-3, cleaved caspase-3, Keap1 and Nrf2 proteins; immunofluorescence was used to detect Nrf2 cells. Protein into the nuclear situation. Results Shikonin inhibited the proliferation of H9c2 cells in a concentration-time-dependent manner (P＜0.05). H/R induced apoptosis of H9c2 cells, cell cycle arrest and promoted the expression of Bax and cleaved caspase-3 proteins, inhibited the expression of Bcl-2 protein (P＜0.05). Shikonin inhibited apoptosis, relieved cell cycle arrest, and cleaved caspase-3 and Bax protein expression, and increased Bcl-2 protein expression in a concentration-time-dependent manner; Shikonin decreased the active oxygen, MDA and 8-OHdG induced by H/R, increased the GSH content induced by H/R and down-regulated the expression of γ-GCS, HO-1 and NQO1 mRNA, caused an increase in Nrf2 protein and down-regulation of Keap1, and promoted Nrf2 protein entry into the nucleus (P＜0.05). Conclusions Shikonin attenuates myocardial cell injury induced by hypoxia-reoxygenation in H9c2 cells.

Key words: shikonin, oxidative stress, hypoxia-reoxygenation