AS-IV attenuates mesangial matrix expansion in a rat model of diabetic nephropathy. A–D: Representative images of PAS stained kidney tissue (×400). A, Normal group; B, Model group; C, AS-IV group; D, PBA group. E: The ratios of mesangial area to total glomerular area were averaged from 30 glomeruli per rat. Data are presented as the mean ± SD. △P < 0.05 vs. Normal, *P < 0.05 vs. Model.