HBO preconditioning had no effect on Nrf2 regulation, and significantly reduced HO-1 expression. Representative immunoblots and densitometric analysis of Nrf2 in nuclear fraction (A), Nrf2 in cytosolic fraction (B), and HO-1 in cytosolic fraction (C) at 24 h after MCAO. HBO-PC had no effect on Nrf2 regulation. Furthermore, HO-1 was downregulated by HBO-PC. *P> 0.05 vs. htMCAO, #P> 0.05 vs. sham.