Schisandra chinensis extract ameliorates myocardial ischemia/reperfusion injury via TLR4/NF-κB/MyD88 signaling pathway

Purpose: To investigate the effects of Schisandra chinensis extract (SCE) on myocardial ischemiareperfusion (I/R) injury and to elucidate its underlying mechanism of action. Methods: A rat model of myocardial I/R injury was used. Ischemia was induced by occluding the left anterior descending artery for 30 min and the myocardium was then reperfused for 2 h in Sprague-Dawley rats. Triphenyltetrazolium chloride (TTC) staining was used to measure myocardial infarct size, while the levels of inflammatory cytokines were evaluated by enzyme-linked immunosorbent assay (ELISA). Western blot assay was conducted to determine protein levels. Results: TTC staining showed that myocardial I/R injury was ameliorated after SCE treatment. Serum creatine kinase (CK), lactate dehydrogenase (LDH), and malondialdehyde (MDA) levels decreased, whereas superoxide dismutase (SOD) activity increased after SCE treatment. Moreover, seruminterleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α) expression levels were reduced after SCE treatment. Furthermore, SCE treatment remarkably downregulated the protein expression levels of Toll-like receptor 4 (TLR4), nuclear factor-kappa B (NF-κB), and myeloid differentiation factor 88 (MyD88). Conclusion: SCE may exert protective effects against myocardial I/R injury by downregulating TLR4-mediated NF-κB/MyD88 signaling pathway. However, this needs to confirmed in clinical studies. Keywords: Schisandra chinensis, TLR4/NF-κB/MyD88, Inflammasome, Myocardial ischemiareperfusion injury