Study Of TGF-β1 Induced Airway Remodeling In Asthma

Many factors participate in the process of airway inflammation in asthma. These include antigens, inflammatory mediaters and cytokines et al. And airway remodeling occurs with airway inflammation. So airway remodelingis one of early events in the process of asthma. Airway remodeling includes the shedding of epithelium, thickening of airway wall,subepithelial collagen deposition, airway smooth muscle hypertrophy/hyperplasia and increased submucosal vascularity and remodeling. The airway smooth muscle hypertrophy and hyperplasia is one of important factors in the process of airway remodeling. Because airway smooth muscle hypertrophy and hyperplasia can increase bronchial hyperresponsiveness and increase inreversible airflow obstruction. Until now the pathogenesis of airway remodling and airway smooth muscle cell proliferation is not clear. To investigate thepathogenesis and antiproliferation of ASMCs may help the treatment of asthma.Transforming growth factor 3 (TGF-3 ) is a pleiotropic cytokinewith the potential to be involved in both inflammatory and fibrotic process. It can act as an immunomodulator, having both inductive and suppressive effects on inflammation and the immune response. TGF- 3 expression has also been reported to be increased in asthmatic subjects with more severe disease. The cellular source of TGF-3 have been ascribed primarily to bronchial epithelial cells and inflammatory cells, especially lymphocytes ,eosinophils and neutrophils. Chronic airway inflammation and the associated remodeling process, in particular subepithelial f ibrosis, are likely to contribute to the pathogenesis of asthma. But the dirrect effects of TGF- 3 on airway smooth muscle cellsis not clear.So we investigated the effects of TGF-3 on airway smooth musle proliferation.The stimulation of inflammatory mediators and cytokines to rat airway smooth muscle cells are conducted by different signal pathways. So the extracellular sgnals can be conducted into cells. This will start or depress certain geng expression. The cell cycle started at the end of the process. MARK pathway and PI-3K pathway are two important pathway in extracellular sgnals conducting into cells. In our study U-0126, the inhibitor of ERK1/2, one of the key kinasein MAPK and LY294002,the inhibitor of PI-3K were used to block the two signal pathway, through which wedetect the signal pathway in TGF- 3 1 induced airway smooth muscle proliferation.1.TGF- 3 1 induced rat airway smooth muscle cells proliferationThe experiment is designed to observe the effects of transforming growth factor P 1 (TGF-1) on airway smooth muscle cells (ASMCs) proliferation in rat . ASMCs is cultured in different concentration of TGF- 3 1 and the proliferation of ASMCs is detected by MTT and flow cytometer. Through MTT the values of OD of 10 H g L-1 TGF-3 1 group and 100 u g L-1 TGF- 1 group were significantly higher than control group and 10%FCS/DMEM group in day 2. The values of OD of 10%FCS/DMEM group were higher than those of control group in day 3. Under the microscope the ASMCs of 10 g L-1 TGF- 3 1 group and 100 11 g L-1 TGF- 1 group are confluent in 3 days in 96-well plates but 5 days in 100 11 g L-1 TGF- 1 group and 10% FCS/DMEM and group. The cell cycle detected by flow cytometer shows S phase and G2 phase cells ,which are induced by TGF-3 1 are increased. TGF-3 1 significantly promoted the proliferation of ASMCs in rat.2.Signal transduction in TGF-3 1 induced rat airway smooth muscle cells proliferationTo investigate possible intracellular signal pathway involved in TGF-3 induced rat airway smooth muscle cells proliferation we used extrcellular signal-regulated kinasel/2(ERKl/2) inhibitor U-0126 or PI-3K inhibitor LY294002 to block the two signal pathway, through which wedetect the signal pathway in TGF-β 1 induced airway smooth muscle proliferation. We found primarily U0126 suppressed TGF-β 1 induced airway smooth muscle proliferation but not LY294002. The expression of phospho-p42/p44 ERKs examined by immunocytochemistry image analysis...