Study on the Protective Effect of Schizandrin B against Acetaminophen-Induced Cytotoxicity in Human Hepatocyte

Drug-induced liver injury (DILI) occurs frequently worldwide. Acetaminophen (APAP) is a common drug causing DILI. Current treatment methods are difficult to achieve satisfactory results. Therefore, there is an urgent need to provide safe and effective treatment for patients. Schizandrin B (Sch B), the main component of Schisandra, has a protective effect on liver. However, the potential mechanism of Sch B in the treatment of APAP induced liver injury has not been elucidated to date. In our research, we studied the effect of Sch B on protecting damaged liver cells and explored the potential mechanism underlying its ability to reduce APAP liver injury. We found that Sch B could reduce hepatocyte apoptosis, oxidative stress injury and inflammatory response. These effects were positively correlated with the dose of Sch B. Sch B regulated glucose 6-phosphate dehydrogenase expression by upregulating the expression of p21-activated kinase 4 and polo-like kinase 1. Sch B could inhibit the mitogen-activated protein kinase (MAPK)-c-Jun N-terminal kinase (JNK)-extracellular signal-regulated kinase (ERK) signaling pathway and regulate the expression of apoptosis-related proteins to reduce the incidence of cell apoptosis. In addition, Sch B reduced the expression levels of reactive oxygen species and inflammatory cytokines in hepatocyte. Consequently, we described for the first time that Sch B could not only activate the pentose phosphate pathway but also inhibit the MAPK-JNK-ERK signaling pathway, thereby achieving antioxidative and anti-inflammatory effects and inhibiting hepatocyte apoptosis. These findings indicated the potential use of Sch B in curing liver damage induced by APAP.