Figure 1.

Decreased bone morphogenetic protein 7 and increased transforming growth factor-beta 1 in carbon tetrachloride-induced liver fibrotic mice. Mice were challenged by intraperitoneal injections of carbon tetrachloride (CCl₄) or control vehicle (Control, corn oil as the vehicle) as described in Materials and Methods. The severity of liver fibrosis was evaluated by using the measures, including A: Masson’s trichrome staining of fibrotic areas (by collagen deposition, 100×); B: Morphometric analysis of fibrotic lesions in the liver; C: Western blot analysis of expression of BMP7 and TGF-β1. At the indicated time points after CCl₄ injection (2 d, 1 wk, 2 wk, 3 wk, and 4 wk), equivalent amount of whole liver detergent lysates were blotted for detecting BMP7 and transforming growth factor-beta 1 (TGF-β1). The level of BMP7 protein expression first rose and then fell, which significantly decreased at 4 wk, while TGF-β1 expression showed a gradual upward trend; D: Trend chart of BMP7 and TGF-β1 protein expression in liver-injured mouse model induced by CCl₄. ^cP < 0.01 or ^dP < 0.01 compared to time point 0, ^eP < 0.05 compared to time point 2 wk; E: Western blot analysis of expression of p-Smad3, p-Smad1/5/8, α-SMA, and Col I. At the time point 4 wk, equivalent amount of whole liver detergent lysates were blotted for detecting p-Smad3, p-Smad1/5/8, α-SMA (a marker for myofibroblast differentiation), and Col I. Each lane represents one individual mouse. GAPDH was used as a loading control; and F: Densitometry analysis of the expression of p-Smad3, p-Smad1/5/8, α-SMA, and Col I. Data are pooled and represented as the mean ± SE, n = 8 animals per group. ^bP < 0.01. BMP7: Bone morphogenetic protein 7; p-Smad3: Phosphorylated Smad3; CCl_4: Carbon tetrachloride; TGF-β1: Transforming growth factor-beta 1; Col I: Collagen I; α-SMA: Alpha-smooth muscle actin.