Qingda Granules Alleviate Lipopolysaccharide-induced Microglial Oxidative Stress Response Via P38MAPK/Nrf2/HO-1 Pathway

Objective:To study the antioxidant effect of Qingda Granules(QDG)on lipopolysaccharide(LPS)-induced activation of BV-2 microglia and explore its possible effects on the activation of p38MAPK/Nrf2/HO-1 anti-oxidation transduction signal pathway.Methods:1.Cultivate BV-2 microglial cells in vitro and LPS(1μg/mL)was used to establish the oxidative response model and use MTT method to determine the appropriate intervention concentration range of QDG,which within this concentration range will not cause toxicity to the cells,and the appropriate intervention concentration range when these two materials are used in combination.Afterwards,the experiment was divided into five groups: control group,LPS group,LPS+QDG group,and LPS+QDG group with 31.25,62.5 and 125 μg/mL these three concentration groups.2.Detect the fluorescence intensity of nitric oxide(NO)and reactive oxygen species(ROS)in each group of cells,and detect the content of malondialdehyde(MDA)in the cell supernatant and the activity of Superoxide dismutase(SOD)and glutathione peroxidase(GSH-Px)in the cell supernatant.3.Elisa method to detect the concentration of TNF-α in the cell supernatant of each group.4.Western Blot method to detect the protein expression of p38MAPK(p38),phosphorylated p38MAPK(p-p38),transcription factor Nrf2,nucleus Nrf2,heme oxygenase-1(HO-1)and the expression level of LPS-induced HO-1 protein in BV-2 cells interferes with p38 MAP kinase inhibitor(LY2228820)and QDG.Results:1.LPS concentration of 1 μg/mL and below does not cause toxicity to BV-2 cells,and Qingda Granules at 125 μg/mL and below does not cause toxicity to BV-2 cells.Interferes with LPS(1 μg/mL)and QDG(125 μg/mL and below)in combination did not cause toxicity to BV-2cells.2.The LPS + QDG group can significantly reduce the fluorescence intensity of ROS and NO in microglia cells and the content of MDA in the cell supernatant,and enhance the activity of GSH-Px and SOD antioxidant enzymes in the cell supernatant.3.The LPS + QDG group can significantly reduce the concentration of TNF-α in the activated microglia supernatant.4.The LPS + QDG group significantly increased the expression of p-p38 and HO-1 protein in activated microglia,and significantly increased the expression of Nrf2 protein in the nucleus.Compared with LPS+QDG group,the expression of HO-1 protein in microglia decreased significantly in LY2228820+LPS+QDG group.However,compared with LY2228820+LPS group,the expression level of HO-1 protein in microglia is still significantly increased in LY2228820+LPS+QDG group.Conclusion:1.Qingda Granules can effectively reduce LPS-induced oxidative stress response in BV-2microglia cell.2.Qingda Granules may reduce LPS-induced microglia oxidative stress response by regulating p38MAPK/Nrf2/HO-1 antioxidant signaling pathway.