Distribution of small vessels in ischemic skeletal muscle on Day 14 following CLI induction. A to F) Quantification of small vessels (black arrows) (≤ 15 μm in diameter) through immunohistochemical staining of alpha-smooth actin (α-SMA). G) Number of vessels in ischemic muscle for each group (n = 6) on Day 14 following CLI induction. In DPP4-deficient animals, significantly lower number of small vessels in those with or without GCSF treatment than in DPP4D-NC, but similar between the former two groups. * vs. †, P < 0.03. In WT Fischer rats, significantly higher number of small vessels in WT-NC than in those with or without GCSF treatment, and higher in those with GCSF treatment than in those without. * vs. † vs. ‡, P < 0.001. Scale bars in right lower corner represent 50 μm. For comparison among the six groups, statistical analysis by one-way ANOVA. * vs. other groups, P < 0.001. Symbols (*, †, ‡) indicate significant difference (at 0.05 level) by Bonferroni's multiple-comparisons post hoc test.