Fluoro-Jade B histofluorescence staining in CA1 of the (A) NT/control, (B) NT/sham, NT/IR at (C) 2, (D) 3 and (E) 5 days after IR, (F) HT/control, (G) HT/sham and HT/IR groups at (H) 2, (I) 3 and (J) 5 days after IR. In the NT/IR group, numerous FJB-positive cells were detected in the SP at 5 days after IR. However, in the HT/IR group, several FJB-positive cells were found from 2 days after IR. Scale bar, 50 µm. (K) Numbers of FJB-positive cells in CA1. *P<0.0001 vs. NT/sham or HT/sham group; †P<0.0001, significantly different from the corresponding NT group; #P<0.0001 vs. pre-time point group. The bars indicate the means ± SEM. SO, stratum oriens; SR, stratum radiatum; CA1, cornu ammonis 1; IR, ischemia/reperfusion; NT, normothermia; HT, hyperthermia; SP, stratum pyramidale.