Histological staining with Periodic acid-Schiff's (PAS) in glomeruli (A-C) shows the glomerular and tubulointerstitial structure of a normal rat kidney (A), diabetic rat kidney (B), in which significant changes in glomerular and tubulointerstitial structure were noted. Diabetic rat developed the pathological characteristics of early diabetic nephropathy, including glomerular hypertrophy, mesangial expansion and sclerosis of glomerulus (B). (C) Diabetic rat treated with curcumin showed amelioration of sclerosis of glomerulus. D-F: immunohistochemistry staining for macrophage (ED-1-positive cells). G-I: immunofluorescence staining for ICAM-1 in glomeruli. Kidney tissues were harvested from normal rat as a control (A, D, G), diabetic rat (B, E, H) and curcumin-treated rat (C, F, I). Quantification results are shown for glomerulosclerosis index in each group (J) and number of macrophages (ED-1-positive cells) (K). Values are means ± SEM. **p < 0.05 vs C; ##p < 0.05 vs D (J). **p < 0.01 vs C; ##p < 0.01 vs D (K).