Fig. 4

Deleting Hpx and HO2 reduces activated microglia. The distribution and morphology of microglia (Iba1 positive) can be seen in coronal sections collected at 24 and 72 h from WT and Hpx^−/− mice (a). Activated microglial cells were observed in and around the injury region after the SFHb injection (#2, with large cell bodies bearing short and thick processes) in contrast with resting microglia in the vehicle group (#1, with small cell bodies bearing ramified long and fine processes). Stars indicate cell bodies and arrows present cell processes. Quantitative analysis demonstrated that HO2^−/− and Hpx^−/− mice had less activated microglia at 24 and 72 h than WT mice. In addition, 72 h after injection, their activated microglia cells were significantly increased compared with those at 24 h (b). Scale bar, 50 μm; values represent means ± SEM.*P < 0.05, **P < 0.01, and ***P < 0.001, compared to WT mice; #P < 0.05 compared to 72 h, one-way or two-way ANOVA followed by Newman-Keuls or Bonferroni comparison tests (n = 5–6)