Microvascular alterations after irradiation alone or treatment with BM-derived EPCs. (a) MVD per unit area expressed as number of microvessels per mm2. (b) ALP positive tissue area as % of total tissue. (c) vWF positive tissue area as % of total tissue compared to age-matched untreated (or sham treated) controls. Each bar represents the mean (± SEM) for at least 5 mice per group.