CLDN5 and ischemia: Zo-1 and claudin-5 mRNA expression level was significantly decreased at 6, 12 and 24 h following MCAO (Fig. 6A, B; #P < 0.05); however, at 6, 12 and 24 h after 10 % HS treatment, Zo-1 and claudin-5 were increased significantly when compared with the corresponding ischemia group (Fig. 6A, B; *P < 0.05).