Overexpression of renal Smad7 inhibits renal fibrosis in diabetic rats. A–C: Collagen I expression. D–G: Collagen IV expression. Results show that when compared with diabetic rats (DM) and diabetic rats with control vector treatment (VC), Smad7 gene transfer significantly inhibits renal collagen I and IV expression as demonstrated by immunohistochemistry (A, B, and D–F) and real-time PCR at the mRNA levels (C and G). Data represent mean ± SE for groups of six animals. *P < 0.05, **P < 0.01, ***P < 0.001 vs. normal; #P < 0.05, ###P < 0.001 vs. DM and VC mice. Magnification ×200 (A and D). (A high-quality color representation of this figure is available in the online issue.)