Effects Of Atorvastatin On The Differentiation Of Pulmonary Myofibroblast Induced By Transforming Growth Factor-β₁

ObjectiveIdiopathic pulmonary fibrosis is a kind of unknown etiology, pathogenesis unclear, the lack of treatment means fatal interstitial lung disease. The pathologic features of idiopathic pulmonary fibrosis includes alveolar epithelial cell injury, fibroblast cell foucs as well as the formation of the ECM deposition over, which eventually led to the structure of abnormal lung tissue remodeling. In recent years the study found that fibroblasts focus is mainly composed by myofibroblasts, which are the cause abnormal deposition of extracellular matrix of the main cells. The symbol product of myofibroblasts isα-SMA. Matrix metalloproteinases plays an important role in the synthesis and degradation of extracellular matrix. At the same time research has shown that TGF-β₁ is the key factor to be fibrosised, which can be induced the differentiation of fibroblast cells to myofibroblast. In recent years the study has confirmed that he statin drug that HMA-CoA reductase inhibitory can inhibite fibroblast proliferation and collagen synthesis in vitro, that showed an encouraging trend in pulmonary fibrosis, but the mechanism is not clear. In this experimental study , the TGF-β₁-induced myofibroblast differentiation as a starting point, after the intervention of atorvastatin, observe the changes ofα-SMA and TGF-β₁-induced expression of collagen matrix I, to further explore the mechanism that statin drugs inhibit the pulmonary fibrosis.Material and MethodsInstillate BLM into intratracheal to replicate model of pulmonary fibrosis in rats, instillate saline into intratracheal as the control group, then isolate and culture lung fibroblasts. When the cells naturally purified to the fourth generation, using Atorvastatin as intervention ,then divide the cells into the blank group, TGF-β₁-induced group and the different doses of atorvastatin blocking group. Observating the counting of cells proliferation by the MTT method, theα-SMA expression by immunohistochemical staining statutory, and collagen I content in cell culture supernatant by the ELISA method.ResultsSaline control group, most of the cells are form rules and small, the cytoplasm is clear, the speed of growth is relatively slow, after passage by the speed will be faster. BLM of the experimental group compared with the control group, cells are irregular and big ,also have a high proportion of nuclear Pulp, the growth rate significantly faster than the control group.Effects of atorvastatin onα-SMA which is the hallmark of pulmonary myofibrobl- asts induced by TGF-β₁ is significantly inhibited.Atorvastatin can inhibit the proliferation of pulmonarymyofibroblast induced by TGF -β₁ . The cell growth of 5μmol/L atorvastatin group and the 10μmol/L atorvastatin group was significantly inhibited, the cell number dropped to 70 percent(P<0.05) , the groups of 0.1μmol/L and 1μmol/L atorvastating, cytostatics are not obvious and not statistically significant.Atorvastatin can inhibit the collagen I secreted by rat lung fibroblasts which is induced by TGF-β₁. The expression of collagen I of 5μmol/L and 10μmol/L group was significantly reduced, up to 50% (P<0.05). Although the expression of collagen I of 0.1μmol/L and 1μmol/L group has a slight decrease, has no statistical significance.ConclusionsAtorvastatin can inhibit the differentiation of myofibroblast induced by TGF-β₁, mainly in cell morphology, cell proliferation and the change ofα-SMA which is the landmark product of myofibroblast, at the same time we find that atorvastatin can reduct expression of collagen I which is the induced matrix of TGF-β₁.