Figure 3.

Double immunofluorescence prolyl 4-hydroxylase/CD31 and prolyl 4-hydroxylase/BrdU in the peri-infarcted area. (A) Double labeling of cells with a P4Hbeta antibody (green) and CD31 (red) revealed that under hypoxic conditions P4Hb-positive fibroblasts/fibrocytes seems to emanate from the vascular wall (inset, arrowheads) a process that was more evident in young brains. (B) In the aged animals, we noted a preferential agglomeration/accumulation of fibroblasts in the scar region. (C) Double labeling of cells with a P4Hb (green) and the proliferation marker BrdU (blue) in aged rat brains revealed that some proliferating fibrocytes/fibroblasts had BrdU-positive nuclei in the peri-lesional area (arrowheads). Eventually, some co-labeled cells emanated from the capillary wall [(C), inset, arrowheads]. (D) At day 14 post-stroke, the vascular density was higher in the peri-infarcted area of young animals as compared to the similar region of aged rats (twofold). However, beyond the inhibitory fibrotic scar, the vascular density was similar in the two age groups. (A–C) represent Z-projection images.