Figure 4

Photomicrographs representing LRP-1 immunohistochemistry of an adult control animal that is positively stained with LRP-1 (positive control; A, E), 21-day saline controls (B, C, D), and age-matched hydrocephalic animals (F, G, H). Black arrows represent blood vessels that are positively stained with LRP-1 proteins. These are characterized by either dark brown punctate particles (D, G) or diffused profiles (A, B, C, F). The asterisks represent non-specific staining of neuron and glial cell bodies. At higher magnification (E) positive LRP-1 labeling can be seen both within the endothelial lining (black arrow) of a capillary deep within the cerebral cortex, as well as in the neuropil immediately adjacent (yellow arrow) to the microvessel. In the choroid plexus of 21-day controls (B), LRP-1 labeling appears throughout the cytoplasm of epithelial cells but seems more intense on the apical surface adjacent to CSF. In 21-day hydrocephalic animals (F), LRP-1 labeling is also present throughout the cell but seems denser in central regions of the cell, which may mean that LRP-1 has translocated to the nucleus. Insets show these features at higher magnification. There are minimal changes between the hydrocephalic animals (G, H) versus the saline controls (C, D), i.e. only a slight increase in the cortex and a slight decrease in the hippocampus. In D and G, the insets represent a higher magnification to show the punctate character of some LRP-1 labeling. Scale bar = 25 μm.