The suppression effects of thalidomide on human lung fibroblasts: Cell proliferation, vascular endothelial growth factor release, and collagen production

Background: Expression of transforming growth factor (TGF)- β₁ and increases in angiogenesis and deposition of extracellular matrix are the key features of tracheal granulation formation. The aim of this study was to investigate the potential role of thalidomide in preventing granulation tissue formation from the aspect of cellular effects in vitro, including fibroblast proliferation, vascular endothelial growth factor (VEGF) release, and collagen production. Methods: Human lung fibroblasts were obtained from bronchus and cultured. The effects of thalidomide on cell proliferation, migration, TGF-β₁-induced VEGF, and signal pathway were investigated. Results: Thalidomide (20 μM) not only inhibited cell proliferation after 24 h [fold increase of cell number, 0.85 ± 0.09 vs. 1.47 ± 0.14 (treatment vs. control group); P < 0.01] and 48 h of incubation (0.85 ± 0.10 vs. 1.97 ± 0.12; P < 0.001), it also inhibited cell migration and slowed wound closure at 24 h (P < 0.001). Thalidomide significantly attenuated TGF-β₁-induced VEGF expression at both the mRNA and protein levels. Incubation of thalidomide with cells stimulated with TGF-β₁ significantly inhibited their production of collagen. Thalidomide inhibited Smad3, STAT3, and subsequent p44/42 kinase phosphorylation. Conclusion: Thalidomide may inhibit human fibroblast proliferation and it is worthy of further in vivo investigation.