Expression of kidney injury molecule (KIM-1) in kidney of mice in each group. (a) KIM-1 immunohistochemical staining of mouse renal tissues from each groups (×400). N1–N2 = Negative control group, M1–M2 = MG53-treated group, B1–B2 = BSA-treated group. Scale bar denotes 100 µm. (b) KIM-1 protein expression in each group. The mean optical density score in the MG53-treated group was significantly lower than that of the BSA-treated group (240,190.9 ± 58,277.4 vs 342,880.3 ± 36,821.7, P < 0.001).