A UUO model was induced in WT, Aldh2*1/*2, and Aldh2*2/*2 mice (n = 5 for each group), and kidneys were collected 7 days after surgery. (A) H&E and periodic acid–Schiff (PAS) staining to assess morphological changes in kidney tissues (first and second panels). Sirius red staining evaluates the kidney fibrosis area on day 7 after UUO (third panel). Immunohistochemistry for Acr-PCs in kidney tissues is presented in the fourth panel. Scale bar: 50 μm. (B) The upper panel shows Western blot analysis of Acr-PC in kidney tissues, with quantification of these proteins shown in the lower panel. (C) The left panel shows Western blot analysis of collagen 1, α–smooth muscle actin (α-SMA), and ALDH2 in kidney tissues, with quantification of these proteins shown in the right panel. mRNA expression of (D) Col1a1, Acta2, (E) Havcr1, Lcn2, and (F) Il6 and Il1b in kidney tissues was assessed using quantitative reverse transcription PCR analysis. Data are presented as mean ± SD. Statistical significance was determined using Kruskal-Wallis tests, and 2-tailed P values are shown. *P < 0.05, **P < 0.01, ***P < 0.001 compared with the WT group. Acr-PCs, acrolein-protein conjugates; ALDH2, aldehyde dehydrogenase 2; WT, wild-type; UUO, unilateral ureteral obstruction; Acta2, actin alpha 2; Aldh2, aldehyde dehydrogenase 2; Col1a1, collagen type I alpha 1 chain; Havcr1, hepatitis A virus cellular receptor 1 homolog; Il6, interleukin-6, Il1b, interleukin-1β; Lcn2, lipocalin-2.