Fig 4. Inhibition of retinol metabolism by 4-MP suppresses HSC activation in CCl₄-induced liver fibrosis.

Mice were concurrently treated with CCl₄ and 4-MP for 2 weeks and HSCs were isolated from the treated mice. (A) Representative Western blot images for α-SMA, TGF-β1, pSmad3, and ADH3 in isolated HSCs and quantification of respective images. Semi-quantitative PCR (B) and qPCR (C) for α-SMA, TGF-β1, COL1A1, MCP-1, and IL-6 in isolated HSCs. (D) Retinol and their metabolites, all trans-retinaldehyde (atRald) and retinoic acid (atRA), in isolated HSCs. Treatment with 4-MP increased retinol levels and reduced its metabolites significantly. The data are representative of three independent experiments and are expressed as mean ± SEM. *P < 0.05, **P < 0.01 compared with the respective controls.