Protective effect of celastrol on myocardial ischemia-reperfusion injury

Objective: Celastrol, a major active constituent of Tripterygium wilfordii, has antioxidant, anti-inflammatory, and anticancer effects. However, whether celastrol can exert protective effect on myocardial ischemia-reperfusion injury (MIRI) is unknown. The aim of this study was to test the protective effect of celastrol on MIRI and elucidate its underlying mechanism. Methods: Cardiomyocytes (H9c2 cells) were subjected to hypoxia for 8 h followed by reoxygenation for 4 h to create hypoxia/reoxygenation (H/R) model, an in vitro MIRI model. Celastrol was added to the medium 60 min before the H/R process. Cell viability was detected using MTT assay. Myocardial injury was evaluated by measuring lactate dehydrogenase (LDH) and creatine kinase MB isoenzyme (CK-MB) activity. Changes in mRNA and protein expression of TNF-alpha, IL-1 beta, and nuclear factor-B-kappa (NF-B-kappa) were measured with RT-qPCR assay and western blot analysis. Results: Results showed that low-dose celastrol (20 and 50 nM) treatment significantly increased cell viability and decreased LDH and CK-MB activity in the condition of H/R, but high-dose celastrol (200 and 400 nM) resulted in extra injury to cardiomyocytes. Moreover, treatment with 50 nM celastrol significantly downregulated mRNA and protein expression of TNF-alpha and IL-1 beta. Meanwhile, NF-B-kappa mRNA and protein in the nucleus were also correspondingly reduced. Conclusion: Our study demonstrated that low-dose celastrol could prevent MIRI in cardiomyocytes by inhibiting the activation of NF-B-kappa, and celastrol may be a potential therapeutic agent for preventing MIRI.