Effects of Cigarette Smoke Extract on the Proliferation and Secretion of Hydrogen Peroxide in Human Lung Fibroblasts Induced by Transforming Growth Factor-β1 / 中国呼吸与危重监护杂志

ABSTRACT

Objective To observe the effects of cigarette smoke extract (CSE) on the proliferation and secretion of hydrogen peroxide (H2O2) in human lung fibroblasts (HLFs) induced by transforming growth faetor-β1(TGF-β1).Methods Cultured HLFs were divided into a normal group and a model group induced by TGF-β1 (5 ng/mL),then intervened with CSE at different concentrations (0% ,2.5% ,5%, 10%, respectively).Brdu ELISA assay was used to detect cell proliferation.H2O2release from cultured cells was assayed using a fluorimetric method.Cellular localization of H2O2 and expression of α-SMA were performed using a fluorescent-labeling strategy.Results TGF-β1 stimulated group showed positive expression of α-SMA, implying TGF-β1 had induced fibroblasts to differentiate into myofibroblasts.In TGF-β1 stimulated group,2.5% and 5% CSE promoted cell proliferation (P < 0.01 or 0.05), while 10% CSE inhibited cell proliferation (P < 0.01).In the normal group, both low and high concentration of CSE inhibited cell proliferation (P < 0.01 or P < 0.05), and the inhibition effect was dose-dependent.HLF induced by TGF-β1 generated low constitutive levels of extracellular H2O2 that was markedly enhanced by CSE treatment (P < 0.01).Pretreatment with DPI, an inhibitor of NADPH oxidase, abolished secretion of H2O2.Cellular localization of H2O2 by a fluorescent-labeling strategy demonstrated that extracellular secretion of H2O2 is specific to the myofibroblast.Conclusions Low concentration of CSE can promote myofibroblast proliferation, and markedly increase extracellular secretion of H2O2.CSE possibly take part in the development and progress of idiopathic pulmonary fibrosis by increasing oxidative stress.