Rosiglitazone Inhibited The Deposition Of Collagen And Transformation Of Embryonic Lung Fibroblasts And Its Signal Pathways

Objective：The incidence of Idiopathic pulmonary fibrosis (IPF) is thehighest in idiopathic interstitial pneumonia. The pathogenesis of this diseaseremains unknown. The principal characteristics is that the damage of alveolarepithelial cells, the infiltration of inflammatory cells, the aggregation ofmyofibroblasts, and the accumulation of extracellular matrix (ECM).Inflammation and fibrosis are regarded as two important stages in IPF.Rosiglitazone belongs to thiazolidinediones (TZDS). It is syntheticligands of peroxisome proliferator activated receptor gamma which playsbiological functions to combine with ligands. In clinic, PPAR-γ agonists are amedicine of treatment type2diabetes, The present investigation showed thatrosiglitazone could ameliorate the process of pulmonary fibrosis.Rosiglitazone inhibited pulmonary fibrosis by regulating the inflammatoryresponse, by regulating function of macrophages, by promoting apoptosis andtransformation, by decreasing the thick of basement membrane and thedeposition of extracellular matrix. The research of bleomycin-inducedpulmonary fibrosis model confirmed that rosiglitazone could inhibit theprocess of pulmonary fibrosis.Plasminogen activator inhibitor-1is the family member of the serineprotease inhibitor, the main inhibitor of the fibrinolytic system, which caninhibit the activity of urokinase type plasminogen activator (uPA) and tissueplasminogen activator (tPA). Besides, it can combine with vitrein of ECM. Itis the central factor of promoting pulmonary fibrosis by regulating thefibrinolytic system.Presently, it was reported that rosiglitazone could ameliorate the renalfibrosis by inhibiting the expression of PAI-1. In present study, we explore that rosiglitazone ameliorate pulmonary fibrosis by downregulation the expressionof PAI-1and the possible signaling mechanism.Methods:1The embryonic lung fibroblasts were recovery and cultured from theliquid nitrogen.2The effect of rosiglitazone on fibroblasts and its signal pathway.According to our preliminary research, the optimal concentrations ofrosiglitazone and PAI-1are30umol/L and20ug/ml. Cells were divided intoControl, Rosiglitazone (30umol/L) and Rosiglitazone+PAI-1(30umol/L+20ug/ml) groups. The protein expressions of PAI-1, α-SMA, ERK, P-ERK, AKT,P-AKT in24h,48h and72h were determined by Western blot; the mRNAexpressions of PAI-1, α-SMA, collagens type-I and type-III in24h weredetermined respectively by RT-PCR.3Statistical analysisData were expressed as mean±SD (X±SD) and statistically treated withstatistical software of Statistical Program for Social Sciences13.0. One-wayANOVA was applied between observation group and Control, P<0.05wasconsidered statistically significant. The methed of SNK was used to testdifference between groups. P<0.05was considered statistically significant.Results:1Fibroblasts were globular after recovered. Fibroblasts adherence andexpanded on4-5hours. The shape of the fully expanded cells were as thespindle. The cells of3-5passages were used for experiment.2The protein and mRNA levels of PAI-1were significantly decreased in24hours in Rosiglitazone group and the downregulation were continued to72hours. It showed statistically difference compared with the Control group(P<0.05).3The protein levels at24h,48h,72h and mRNA levels at24h of a-SMAwere significantly decreased in Rosiglitazone group compared with controlgroup (P<0.05). After adding extrinsic PAI-1to medium, the levels of α-SMAwere significantly increased in Rosiglitazone+PAI-1group compared with the Rosiglitazone group (P<0.05).4The mRNA levels of collagen type-I and type-III were significantlydecreased in Rosiglitazone group at24h compared with the Control group.After increasing extrinsic PAI-1, the levels of collagens type-I and type-IIIwere significantly increased in Rosiglitazone+PAI-1group compared with theRosiglitazone group (P<0.05).5There were no statistically significant among three groups (P>0.05). Thelevels of ERK/P-ERK in Rosiglitazone group were significantly decreased at24h,48h, and72h compared with the Control group (P<0.05).Conclusions:1Rosiglitazone could inhibit the transformation of fibroblasts into myo-fibroblasts, also could inhibit the synthesis of collagen.2Rosiglitazone could inhibit the expression of PAI-1in the fibroblasts,which increased the activity of fibrinolytic system.3After decreasing the activity of fibrinolytic system by increasingextrinsic PAI-1, it could be attenuated that rosiglitazone ameliorated pulmo-nary fibrosis.4Rosiglitazone inhibited the transformation and the accumulation ofcollagen of lung fibroblasts through ERK/P-ERK signaling pathway.