Reduced Neovascularization in Aged Rats: A Study Using Lipopolysaccharide-induced Inflammation

Abstract

Aged tissues are associated with reduced capillary density and delayed neovascularization. The aging environment is characterized by increased oxidative stress, which damages macromolecules, and thereby causes apoptosis of endothelial cells. Lipopolysaccharide (LPS) has been shown to have angiogenic property. Therefore, the objective of this study was to examine whether neovascularization after LPS-induced inflammation in aged rats is decreased when compared to adult rats. Male Wistar rats were divided into four groups: adult (aged 6-8 months), aged (aged 22-24 months), adult + LPS, and aged + LPS. Blood perfusion, capillary vascularity, plasma and tissue MDA, and tissue VEGF levels were measured. Plasma MDA in aged group was higher than in adult group (P < 0.05). Blood perfusion and capillary vascularity (%CV) in aged group were lower than in adult group (P < 0.05). Blood perfusion and %CV in aged + LPS group were significantly lower than those in adult + LPS group. Aged rats have reduced capillary vascularity when compared to adult rats. LPS could induce neovascularization in both adult and aged rats. However, aged rats have reduced neovascularization after LPS pre-treatment when compared to adult + LPS rats.