Panel 1: Representative photomicrographs of glomerular, tubulo-interstitial and perivascular fibrosis in control (a, d, g), CsA (b, e, h), CsA+C21-treated (c, f, i) rats (sirius red staining: glomerular and tubulo-interstitial fields, ×20; perivascular fields, ×40). Staining showed an increase in glomerular and tubulo-interstitial fibrosis in CsA-treated rats (b and e) as compared with control rats (a and d). C21 treatment (c and f) did not modify glomerular and tubulo-interstitial fibrosis in CsA-treated rats. Perivascular fibrosis did not change both in CsA-treated rats (h) and CsA+C21-treated rats (i). Panel 2: Quantification of glomerular, tubulo-interstitial and perivascular fibrosis in the different groups of rats. Data are means ± S.E.M. *P<0.01 compared with control group.