Protection and mechanism of oxygen glucose deprivation exposed astrocytes by nuclear factor⁃erythroid 2⁃related factor 2 signal pathway activation

Objective To analyze the protective effect and mechanism of nuclear factor⁃erythroid 2⁃related factor 2 (Nrf2) signal pathway agonist tertiary butylhydroquinone (tBHQ) on astrocytes under oxygen glucose deprivation (OGD). Methods Astrocytes were divided into 3 groups: the control group, the OGD group, and the tBHQ group. The cell proliferation activity after OGD and tBHQ intervention was assessed using the CCK⁃8 assay. Oxidative stress levels were evaluated by measuring superoxide dismutase (SOD) activity and malondialdehyde (MDA) content. The relative expression levels of pyroptosis-related genes (Caspase-1, NLRP3, IL-1β, IL-18) and antioxidant⁃related genes (HO-1, NQO1) were detected using real time fluorescent quantitative polymerase chain reaction (PCR). Results Significant differences were observed among different treatment groups in cell proliferation activity (F=8.676, P=0.003), SOD activity (F=5.818, P=0.013), MDA content (F=9.049, P=0.004), relative expression of pyroptosis⁃related genes Caspase⁃1 (F = 17.926, P = 0.003), NLRP3 (F=10.164, P=0.012), IL⁃1β (F=13.472, P=0.006), IL⁃18 (F=8.292, P=0.019), and antioxidant⁃related genes HO-1 (F=30.468, P=0.001), NQO1 (F=29.621, P =0.001). Compared with the control group, the OGD group exhibited reduced cell proliferation activity (t=4.114, P=0.001) and SOD activity (t=2.149, P=0.029), increased MDA content (t=-2.852, P=0.015), upregulated expression of pyroptosis⁃related genes Caspase⁃1 (t=⁃3.759, P=0.009), NLRP3 (t=⁃4.119, P=0.006), IL-1β (t =⁃4.747, P=0.003) and IL-18 (t =⁃3.122, P=0.021), and downregulated expression of antioxidant⁃related genes HO⁃1 (t=3.816, P=0.009) and NQO1 (t=5.303, P=0.002). Following tBHQ intervention, cell proliferation activity increased (t=2.621, P=0.019), SOD activity increased (t=3.292, P=0.005), MDA content decreased (t=⁃4.160, P=0.001), expression of Caspase-1 (t=⁃5.916, P=0.001), NLRP3 (t =⁃3.647, P=0.011), IL⁃1β (t=⁃4.193, P=0.006) and IL⁃18 (t=⁃3.825, P=0.009) decreased, and expression of HO⁃1 (t=7.805, P=0.000) and NQO1 (t=7.483, P=0.000) increased. Conclusions OGD can suppress the expression of antioxidant⁃related genes HO⁃1 and NQO1, promote astrocytes pyroptosis and oxidative stress, and inhibit cell proliferation activity. Nrf2 signal pathway agonist tBHQ can enhance the expression of HO ⁃1 and NQO1, reduce oxidative stress in OGD⁃exposed astrocytes, reverse pyroptosis, and exert protective effects on the cells.