RNA isolation and real-time PCR were performed according to protocols previously described in detail 16 (link). In brief, total mRNA from kidney tissue was extracted using the TRIzol reagent (RNA STAT 60 Tel-Test; Ambion, Austin, TX, USA). cDNA was used in the specific assays by Real-Time PCR system (Life Technologies Corporation, Carlsbad, CA, USA) on demand target mixes (Applied Biosystems, Foster City, CA, USA). The expression levels of mRNA encoding for TGF-β, FN, collagen I, and collagen IV in the kidney tissue were determined and normalized to the level of GAPDH (Applied Biosystems). The cycle times (Ct) were then compared to determine the fold differences between samples.