Cycloastragenol Prevents the Oxidative Damage Induced by t-BHP in C2C12 Cells through Nrf2/HO-1 Pathway
LIU Li1, MA Beibei1, LI Mengjun1, ZHANG Xiaorong1, GAO Yanping2*
The aim of this study was to investigate the protective effect and the mechanism of cycloastragenol on oxidative damage of C2C12 cells induced by t-BHP (tert-butyl hydroperoxide). C2C12 cells were treated with the different concentrations of cycloastragenol, and then with 100 μmol/L t-BHP. Cell viability was measured by CCK-8 assay. EDU-488 assay was used to detect cell proliferation. The intracellular ROS levels were measured by DCFH-DA. The levels of SOD and MDA were detected by biochemical method. The relative expression levels of PAX7, MYOD, Keap1, Nrf2 and HO-1 proteins were detected by Western blot analysis. Nuclear translocation of Nrf2 was characterized by immunofluorescence. Compared with the t-BHP group, cycloastragenol improved the viability of C2C12 cells, reduced the content of ROS and MDA, increased SOD activity. In addition, cycloastragenol promoted the expression of proliferation and differentiation-related proteins (PAX7 and MYOD). Cycloastragenol decreased the expression of Keap1, increased the nuclear expression of the Nrf2 uncoupled to Keap1, and sequentially up-regulated the levels of HO-1. si-Nrf2 inhibited Nrf2/HO-1 signaling pathway, elevated the production of ROS and thus inhibited the protective effects of cycloastragenol in t-BHP-treated C2C12 cells. These results suggested that cycloastragenol againsted t-BHP-induced oxidative injury in C2C12 cells, and its mechanism was probably associated with the inhibition of Keap1 expression, the promotion of Nrf2 nuclear translocation, and the up-regulation of HO-1 expression.
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