SMAD3 and Hepatic fibrosis: Herein, we report the downregulation of p-SMAD3 and TGFβR2 after BM-MSCs administration in rats with liver fibrosis, suggesting the inhibitory effect of BM-MSCs on CCl4-induced fibrosis probably by affecting TGFβ/SMAD signaling pathways through reduction of TGFβR2 and phosphorylation of SMAD3.