Fig. 4

pEPCs tracking. a pEPCs were dyed with CFDA-SE and injected into mice 24 h after UUO surgery. Time points of 0 h, 3 h, 24 h, 48 h, 72 h and 5 days after pEPC injection were chosen to track the fluorescein intensity. An increased fluorescence intensity (red represents the strongest fluorescence intensity) was observed over time after surgery. b Both the operated left kidneys and the non-operated right kidneys were harvested and scanned for fluorescence intensity to eliminate errors. Kidneys presented a much stronger fluorescence on UUO day 5 than at other time points. c, e and f Mice were injected with PKH26 and CFDA-SE-dyed pEPCs and GFP-labelled pEPCs. Sparse pEPCs were found in frozen renal sections or paraffin-embedded renal sections. d Flow cytometry for CFDA-SE showed no significant difference between the operated left kidneys with (UUO+pEPCs-L group) or without pEPCs (UUO+PBS group). g IF staining for GFP (green) and the pEPC marker CD34 (red) showed a phenomenon consistent with PKH26 and CFDA-SE tracking: only sparse GFP and CD34-positive cells were detected in left kidney. All the data are presented as the mean ± SD; n = 2–3/group, and 5 to 6 kidney sections were analyzed. ns, no significant difference. Scale bar, 20 μm