Apoptosis is severe and the TGF-β1/Smad2 signaling pathway is significantly activated in Glt25d1+/− mice. (A) Representative western blots of TGF-β, Glt25d1, cleaved caspase-3, cleaved caspase-9, caspase-9, p-Smad2/3 and Smad2 in the liver. Quantification of individual protein bands of (B) cleaved caspase-3, (C) cleaved caspase-9, (D) TGF-β, (E) p-Smad2 and (F) Glt25d1 were normalized to the corresponding GAPDH levels (n=6–8). *P<0.05, **P<0.01, ***P<0.001; significance determined by Student's t-test or two-way analysis of variance followed by Tukey's test. Glt25d1, collagen β (1-O) galactosyltransferase 1; CCl4, carbon tetrachloride; WT, wild-type; TGF-β, transforming growth factor-β; Smad, small mothers against decapentaplegic; p-, phosphorylated; NS, not significant.