The Effects Of Tranilast On Rats Whith Pulmonary Fibrosis Induced By Bleomycin

Background: Alveolar inflammation and abnormal alveolar structureare the main Features of pulmonary fibrosis （PF）.It is the commonpathological change and end result of mang diffuse interstitial lungdiseases.Many lung diseases can lead to pulmonary fibrosis,such asinterstitial pneumonia and lung diseases caused by connective tissuedisease.PF patients eventually die of respiratory failure,especiallyidiopathic pulmonary fibrosis,mean survival time is3years afterdiagnosis.According to epidemiological data, the morbidity is on rise,because the pathogenesis is unclear, there is no effective or specifictreatment methods and the fatality rate is high.TH1/TH2auxiliary T cellsimbalance has close relationship with pulmonary fibrosis formation.Macrophages、fibroblasts and several other kinds of cells can secreteTGF-β1,and it has a role of promoting fibrosis. Tranilast can inhibit IFN-γsecreted TH1cells and regulate TH1/TH2balance[1]. Tranilast can inhibitthe macrophages activation, reduce fibroblast activity, may have the role ofsuppressing the TGF-β1expression[2]. This paper discusses whethertranilast can regulate the TH1/TH2balance, restrain TGF-β1 expression,has the role of the anti fibrosis.Objective:To study the therapeutic effect and mechanisms of Tranilastrats with pulmonary fibrosis induced by Bleomycin (BLM).Methods: Pulmonary fibrosis was induced in rats by using intratrachealbleomycin and the serum and lungs were collected28days later. The serumlevels of IL4and IFN-γ were determined by ELISA and IL4/IFN-γcalculated. RT-PCR was employed to measure the mRNA expression ofTGF-β1. Immunohistochemistry was employed to detect the proteinexpression of TGF-β1followed by evaluation of alveolitis and fibrosis.Results: When compared with BLM group and glucocorticoid (GC)group, the INF-γ level was markedly increased and IL-4level dramaticallydecreased in the TR group with a significant decrease of IL-4/INF-γ ratio.The mean optical density and mRNA expression of TGF-β1were markedlydecreased accompanied by low scores of alveolitis and fibrosis. Significantdifferences were observed between TR groups (medium and high dose) andBLM group as well as GC group (P<0.05) in the above parameters.Moreover, marked different was also observed among TR groups (P<0.05)in the above parameters.Conclusion：Th1/Th2cytokine balance could be affected in Tranilastgroup, also TGF-β1expression can be reduced.And then,the degree ofpulmonary fibrosis induced by bleomycin in rats of these groups could bereduced.