Abstract:
AIM To investigate the effect of celastrol (CEL) on improving hydrogen peroxide (H2O2)-induced oxidative stress injury in cardiomyocytes by activating nuclear factor E2-related factor 2 (Nrf2)/silent information regulator 3 (SIRT3) signaling pathway.
METHODS AC16 cells were treated with a concentration of 0.5~3.0 μmol/L of celastrol and H2O2. CCK-8 method was applied to measure the cell activity and screen for the optimal concentration of celastrol. AC16 cells were grouped into control group, H2O2 group, low, medium and high concentration celastrol groups (CEL-L+H2O2 group, CEL-M+H2O2 group, CEL-H+H2O2 group) and high concentration celastrol+Nrf2 inhibitor group (CEL-H+ML385+H2O2 group). Flow cytometry was applied to detect cell apoptosis and enzyme-linked immunosorbent assay (ELISA) was applied to detect cellular malondialdehyde (MDA) content, superoxide dismutase (SOD) activity and lactate dehydrogenase (LDH) activity. Immunofluorescence was applied to detect the content of reactive oxygen species (ROS) in AC16 cells and immunofluorescence assay was applied to detect mitochondrial membrane potential (MMP) in cells. Western blot was applied to detect the expressions of B-cell lymphoma associated X protein (Bax), pro apoptotic protein (Caspase-3), Nrf2 and SIRT3 proteins.
RESULTS Celastrol at concentrations of 1.5-2.5 μmol/L was able to promote H2O2-induced proliferation of AC16 cells. Subsequent experiments were conducted at concentrations of 1.5 μmol/L, 2.0 μmol/L and 2.5 μmol/L. Compared with those in the control group, the apoptosis rate, C-Caspase-3, Bax protein expression, ROS, LDH and MDA levels in the H2O2 group were obviously increased, while MMP, SOD levels, Nrf2 and SIRT3 protein expression were reduced (P<0.01). Compared with those in the H2O2 group, the apoptosis rate, C-Caspase-3, Bax protein expression level, ROS, LDH and MDA levels of AC16 cells in the CEL-L+H2O2, CEL-M+H2O2 and CEL-H+H2O2 groups decreased sequentially, while MMP, SOD levels, Nrf2 and SIRT3 protein expression increased (P<0.05, P<0.01). Compared with those in the CEL-H+H2O2 group, the apoptosis rate of AC16 cells, C-Caspase-3, Bax protein expression level, ROS, LDH and MDA levels in the CEL-H+ML385+H2O2 group obviously increased, while MMP, SOD levels, Nrf2 and SIRT3 protein expression decreased (P<0.01).
CONCLUSION Celastrol activates the Nrf2/SIRT3 signaling pathway to alleviate H2O2 induced oxidative stress damage in AC16 cells.