Neuroprotective Effects of Tetrahydroxystilbene Glucoside against Rotenone-Induced Toxicity in PC12 Cells

To investigate the mechanism of the protective effect of tetrahydroxystilbene glucoside (TSG) on nerve cells, an injury model induced by rotenone in PC12 cells was constructed. Cell viability was detected by using cell counting kit-8 (CCK8) assay. Apoptosis was detected by using flow cytometry. The mitochondrial membrane potential (MMP) was detected by using the fluorescent probe JC-1. Generation of reactive oxygen species (ROS) in PC12 cells was determined using the 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate acetyl ester (CM-H₂DCFDA) probe. Protein expression in PC12 cells was detected using Western blotting. The results showed that TSG (20-100 µM) attenuated the cytotoxic effects of rotenone on PC12 cells. TSG pretreatment attenuated the apoptosis rate, the degradation of poly(ADP-ribose)polymerase (PARP) and the activation of cleaved caspase 3, which was induced by rotenone. TSG can significantly reduce the effect of rotenone on the reduction of MMP and the expression of cytoC in the cytosolic fraction. TSG attenuated rotenone-induced de-phosphorylation and mitochondrial translocation of cofilin, as well as rotenone-induced accumulation of ROS. The Western blot results showed that ROT could decrease the expression level of phosphorylated (p)-Glycogen synthase kinase-3β (GSK)-3β and p-AKT, and TSG could weaken these effects of rotenone. In addition, TSG increased the expression level of nuclear factor-E2-related factor 2 (Nrf2) in the nuclear fraction. These results suggest that TSG could protect PC12 cells against rotenone through multiple pathways. Thus, TSG has the potential to become a novel neuroprotective agent.