Figure 3.

Hyperpermeability in Cav-1 KO retina occurs, at least in part, through the paracellular pathway, as can be seen in electron micrographs. A and B: HRP reaction products stain the basement membrane (arrows) in Cav-1 KO vessels (B), but are confined to the lumen in WT vessels (A). Caveolae (arrowheads) are evident in WT vasculature, but absent in KO vasculature. C and D: At higher magnification, it can be seen that HRP reaction product remains on the luminal side of the TJ (boxed region) in a WT vessel (C), but passes through the junction (boxed region) in a Cav-1 KO vessel (D). In WT vessels (C), abluminal caveolae (arrowheads) and luminal, HRP-laden caveolae (v) are apparent. Scale bar = 500 nm. BM, basement membrane; EC, endothelial cell; L, lumen; P, pericyte.