Immunohistochemical results: (A) Immunohistochemical study of Keap1, Nrf2, and HO-1 on brain samples.

Few Keap1-, Nrf2-, and HO-1-positive cells were observed in the control group, which indicates the constitutional activation of Keap1/Nrf2/HO-1 pathway in the normal cortex of rats. High numbers of Keap1-, Nrf2-, and HO-1-positive cells (arrows) were stained brown and observed in the brains of the rats in the subarachnoid hemorrhage (SAH) groups. Significant up-regulation of Keap1, Nrf2, and HO-1 immunoreactivity (arrows) was observed in the neurons and glia cells of SAH brains treated with tBHQ (400X). (B) Quantitative analysis showed relatively low concentrations of Keap1, Nrf2, and HO-1 in the control group. The concentrations of Keap1, Nrf2, and HO-1 expression were higher in the SAH and SAH+vehicle groups. After tBHQ therapy, all three proteins were progressively activated in the treatment group. Bars represent the mean ± SD (n = 10, each group). *P<0.05 compared with control group, #P<0.05 and ##P<0.01 compared with SAH+vehicle group.