Effects of IFR therapy on EPC migration, tube formation, and senescence in vitro. (A,B) Scratch test and modified Boyden chamber assay were used to assess the migratory function of ECFCs in high glucose conditions. Boyden chamber assay using VEGF as a chemoattracting factor was used to evaluate the effects of IFR radiation on EPC migration. (C) An in vitro angiogenesis assay for late ECFCs used ECMatrix gel. Representative photos for in vitro angiogenesis are shown. Cells were stained with crystal violet, and the averages of the total area of complete tubes formed by cells were compared by using computer software. (D) To determine the onset of cellular aging, acidic ß-galactosidase was used as a biochemical marker for acidification, typical for ECFCs senescence. Data are means ± SEM; n = 4 in each experiment.