Tubulointerstitial injury. A: UNx-eNOSKO mice treated with rAAV1-EV shows no evidence of tubular injury. B: Tubular injury is apparent under PAS staining in UNx-eNOSKO mice treated with rAAV1-Flk-sel. C and D: IHC for collagen III in UNx-eNOSKO mice treated with rAAV1-EV (C) or with rAAV1-Flk-sel (D). E and F: Quantitative analysis of collagen III deposition (E) and F4/80-positive macrophage infiltration (F). G and H: TGF-β1 expression in UNx-eNOSKO mice treated with rAAV1-Flk-sel is detected in some tubular epithelial cells under low-power magnification (G, ×200), whereas a high power view revealed TGF-β1 located in the apical epithelial membrane (H, ×630). I and N: Western blotting (WB) of renal cortex for TGF-β1 (H) and its quantification (N). In terms of PDGF-B expression, compared with UNx-eNOSKO mice treated with rAAV1-EV (J), PDGF-B staining (arrow) is enhanced in UNx-eNOSKO mice treated with rAAV1-Flk-sel (K), as shown by its quantification (O). VEGFR2 is expressed (arrows) in UNx-eNOSKO mice treated with rAAV1-EV (L), and expression is pronounced in tubular cells of UNx-eNOSKO mice treated with rAAV1-Flk-sel (M). P: Quantification of IHC for VEGFR2. *P < 0.05, **P < 0.001. Data are expressed as means ± SD; n = 10 in each group. Scale bars = 50 μm.