Experimental Study On The Effect And Mechanisms Of Fufangbiejiaruanganfang Drug Serum On TGF-β Signaling Pathway Mediated By Smads In Hepatic Stellate Cells Of Rat

Hepatic fibrosis is a prosthetic response to chronic liver injury, still a stage of development of kinds of chronic hepatopathy to cirrhosis of liver . The mechanism of hepatic fibrosis is the imbalance of synthesis and degradation of extracellular matrix (ECM) by regulation of many kinds of cells and cytokines. Recently, a lot of data indicate hepatic stellate cells (HSC) is the key cell of formation of ECM and HSC is also the core link of occurrenc of hepatic fibrosis. Various kinds of facts lead to damage of liver, then cause Cellular necrosis of liver and inflammation. Cells which correlated with hepatic fibrosis secrete cytokines to activate HSC to develop mass of ECM, and result in a phenomenon that synthesis of ECM is more than degradation of ECM. Many cytokines regulate activation of HSC. Among these cytokines, transforming growth factor(TGF-β), Platelet derived growth factor (PDGF), insulin-like growth factor-I(IGF-I)are key cytokines. There are five Isoforms TGF-β1~5 express in vertebrate, and TGF-β1~3 express in human and mammal. TGF-βis major cytokine which can stimulate the transdifferentiation of HSC to myofibroblasts(MFB) and promote collagen synthesis. Among them, the ratio of TGF-β1 in somatic cell is the highest(>90%) and the activity of TGF-β1 is most powerful. Transforming growth factor-β1 (TGF-β1) regulates diverse biologic activities including cell growth, cell proliferation, cell death or apoptosis, cell differentiation, and extracellular matrix (ECM) synthesis. TGF-βis believed to be a key mediator of tissuefibrosis as a consequence of ECM accumulation in pathologic states such as systemic sclerosis. TGF-βis known to induce the expression of ECM proteins in mesenchymal cells, and to stimulate the production of protease inhibitors that prevent enzymatic breakdown of the ECM. The first intracellular mediator of TGF-βsignalling that had been identified was Drosophila MAD (Mothers against decapentaplegic), which is involved in the signalling cascade of dpp (decapentaplegic, the Drosophila homologue to TGF-β) signalling [Sekelsky, 1995]. The first vertebrate homologue reported was the tumour suppressor DPC4 (Deleted in Pancreatic Carcinoma, locus 4). In TGF-βsignalling the binding of a ligand-dimer leads to the formation of the receptor complex consisting of an oligomer of receptor type I and II. Receptor type II auto-phosphorylates and phosphorylates the receptor type I which then phosphorylates and activates the receptor-regulated Smad transcription factors. These R-Smads form oligomers with the Co-Smads (Common-mediator Smads) and enter the cell nucleus where they regulate transcription. The antagonistic or inhibitory Smads (I-Smads) negatively regulate these pathways by preventing receptor-mediated phosphorylation of the R-Smads or formation of a functional complex between R-Smads and Co-Smads. Intracellular proteins that mediate signalling from receptors for extracellular TGF β-related factors. Smad2 is essential for embryonic mesoderm formation and establishment of anterior-posterior patterning. Smad4 is important in gastrulation. Smad1 and Smad5 are activated (serine/threonine phosphorylated) by BMP receptors, Smad2 and Smad3 by activin and TGF-βreceptors. Smads activated by occupied receptors then form complexes with Smad4/DPC4 and move into the nucleus where they regulate gene expression. At present, many studies indicate tradition Chinese medicine against hepatic fibrosis have better clinical effect and lower side effect. Our study investigated the inhibitory mechanisms of fufangbiejiaruanganfang against hepatic fibrosis. The prescription of fufangbiejiaruanganfang includes biejia; dangshen; et al. In this study, we investigated the effect of fufangbiejiaruanganfang on TGF-βsignaling pathway including the expression of TGF-βtype I receptor and the expression of downstream mediator of TGF-βsignalingpathway Smad3 protein. Through this study, we will get more understanding about the molecular mechanisms of fufangbiejiaruanganfang against hepatic fibrosis.