Research Paper Advance Articles

Figure 4. Defining the age at which the BBB becomes more susceptible to hypoxia. (A) Frozen brain sections taken from mice of different ages (2–23 months) exposed to hypoxia (8% O₂) for 4 days were dual-stained for CD31 (AlexaFluor-488) and fibrinogen (Cy-3). Images were captured in the midbrain. Scale bars = 100 μm. Quantification of the density of extravascular leaks in the midbrain (B) or olfactory bulb (C) in different age mice following 4 days hypoxia. Results are expressed as the mean ± standard error of the mean (SEM) (n = 5 mice/group). ^*p < 0.05, ^**p < 0.01, ^***p < 0.001. One-way analysis of variance (ANOVA) followed by Tukey’s multiple comparison post-hoc test. Note that the density of vascular leaks increased with age and that major increases were seen between 2–6 months, as well as between 12–15 months in the midbrain.