Representative immunohistochemistry images with pimonidazole staining. (A) Control group. (B) Type 2 diabetic nephropathy group injected with saline. (C–F) Type 2 diabetic nephropathy group injected with 400 mg I/mL of contrast agent (C, 1 h; D, 24 h; E, 48 h; F, 72 h). Pimonidazole staining was mainly localized in the renal outer medulla, especially at 24 h, while the renal cortex was lightly stained following injection of 400 mg I/mL of contrast agent.