Quantitative angiogenesis in spreads of intact rat mesenteric windows.

By introducing a new mode of the recently described mesenteric-window angiogenesis assay (K. Norrby, A. Jakobsson, and J. Sörbo, 1986, Virchows Arch. B. Cell Pathol. 52, 195-206) we measured the entire vascular tree in terms of the vascularized area and the vascular density in spreads of intact mesenteric windows in rats receiving a terminal iv infusion of an ink-gelatin solution to visualize the vessels. Adult and prepubescent rats given ip injections of the mast-cell secretagogue Compound 48/80 or the saline vehicle, as well as untreated litter mates, were used. Following mast-cell activation, both prepubescent and adult rats showed a significant angiogenesis taken as the vascularized area and the vascular density in spreads compared with those of the vehicle-treated animals. In fact the 48/80-treatment increased the vasculature 100-fold compared with the untreated controls. The finding of experimentally induced angiogenesis occurring in rats of all ages should make the assay useful in a wide range of angiogenesis experiments.