UUO surgery was conducted in WT mice (n = 5), and the obstructed kidneys were collected at 7 and 14 days after surgery. (A) Representative kidney gross appearance from WT mice at day 7 or 14 after UUO. (B) The first panel displays periodic acid–Schiff (PAS) staining to assess morphological alterations in kidney tissues. The second panel exhibits Sirius red staining to evaluate the extent of kidney fibrosis on day 7 and 14 after UUO. The third through fifth panels present immunohistochemistry depicting Acr-PC levels, ALDH2, and Vimentin in kidney tissues. Scale bar: 50 μm. (C) The upper panel illustrates Western blot analysis of Acr-PC in kidney tissues of mice at day 7 and 14 after UUO, with quantification of these proteins shown in the lower panel. (D) The upper panel presents Western blot analysis of collagen 1, α–smooth muscle actin (α-SMA), and ALDH2 in kidney tissues of mice at day 7 and 14 after UUO, with quantification of these proteins shown in the lower panel. Data are represented as mean ± SD. Statistical significance was determined using Kruskal-Wallis tests, with 2-tailed P values displayed. *P < 0.05, **P < 0.01, ***P < 0.001 compared with the vehicle control group. Acr-PCs, acrolein-protein conjugates; ALDH2, aldehyde dehydrogenase 2; WT, wild-type; UUO, unilateral ureteral obstruction.