Fig. 6

Fluorescence microangiography (FMA). a–c The green FMA solution injected after sham surgery and UUO 7 days, surrounded with CD31 immunostaining (expressed on the surface of endothelial cells), demonstrates capillary rarefaction in response to the obstructed kidney. The reduced capillary number and perfused area were restored after AMSCs and GDNF-AMSC treatment, especially in the GDNF-AMSC group. Representative images in the box were presented by higher magnification, demonstrating that capillaries surrounded by CD31+ endothelial cells in the UUO group do not appear a luminal FMA signal indicating that these capillaries lack perfusion, but increased FMA perfused area was shown in the GDNF-AMSC group. d–e Both of the individual capillary cross-sectional area and perimeter in the UUO group were smaller than those in the sham group, but AMSC treatment has no good effect on them. These individual capillary markers were significantly improved after GDNF-AMSC treatment in comparison to the AMSC group (*P < 0.05, **P < 0.01, ***P < 0.001)