PF4CreTgfb1^f/fmice have fewer collagen-expressing HSCs and myofibroblasts than WT mice. (A) In situ hybridization of the Col1a2 probe showed higher collagen-expressing cell accumulation in the injured areas of the liver in WT vs PF4CreTgfb1^f/f mice at 3 days and 36 days after CCl₄ challenge. Higher-magnification images (boxed) showed that the morphology of those cells resembled HSCs. (B) To confirm that they were HSCs, liver sections were costained with anti-desmin and collagen antibodies; double-positive cells started to appear at 3 days and in the fibrotic areas at 36 days after CCl₄ challenge. (C) Dual staining with myofibroblast markers αSMA (green) and vimentin (red) showed double-positive (yellow) cells at 36 days after CCl₄ challenge in the WT and PF4CreTgfb1^f/f mice. Quantification of vimentin- (D) and αSMA- (E) positive cells in PF4CreTgfb1^f/f (n = 7) vs WT (n = 12) mice. DAPI, 4′,6-diamidino-2-phenylindole.