Fig. 5
β1 integrin blockade greatly enhances microglial activation in the hypoxic young but not aged brain. Frozen brain sections taken from young (8–10 weeks) and aged (20 months) mice exposed to normoxia or hypoxia (8% O2) that received daily intraperitoneal injections of the anti-mouse β1 integrin function-blocking antibody or isotype control antibody for 4 days were stained for Mac-1 (AlexaFluor-488) and fibrinogen (Cy-3) (A) or CD68 (AlexaFluor-488) and fibrinogen (Cy-3) (B). Images were captured in the midbrain. Scale bars = 100 μm. Quantification of the number of morphologically activated microglia/FOV (C), total Mac-1 area/FOV (D) or number of CD68 + microglia/FOV (E) after 0- or 4-days hypoxia. Results are expressed as the mean ± SEM (n = 6–9 mice/group). *p < 0.05, **p < 0.01, ***p < 0.001. Note that β1 integrin blockade strongly increased all parameters of microglial activation in the young hypoxic brain, but much less so in the aged brain