Keloids are fibroproliferative disorders characterized by the overabundant deposition of extracellular matrix (ECM), especially collagen and overgrowth of scar tissue in response to cutaneous injury. In this study, we isolated a selenium (Se)-containing polysaccharide (Se-ZGTP-I) from Ziyang green tea and explored its potential therapeutic effects on keloid fibroblasts formation. 3-(4,5-Dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and annexin V/propidium iodide (PI) staining assays demonstrated that Se-ZGTP-I or neuron-glia 2 (NG2) short hairpin RNA (shRNA) significantly inhibited proliferation of human keloid fibroblasts via induction of apoptosis. Besides, the activation of caspase-3 and the subsequent cleavage of poly (ADP-ribose) polymerase (PARP) were observed in keloid fibroblasts following Se-ZGTP-I (200 and 400 μg/ml) or NG2 shRNA treatment. Moreover, Western blotting analysis showed that treatment of keloid fibroblasts with Se-ZGTP-I (200 and 400 μg/ml) or NG2 shRNA resulted in an increase of pro-apoptotic protein Bax expression and a decrease in expression levels of anti-apoptotic protein Bcl-2 and NG2. In addition, type I collagen biosynthesis and protein expression in keloid fibroblasts following TGF-β1 stimulation were decreased by Se-ZGTP-I (200 and 400 μg/ml) or NG2 shRNA management. Current findings imply that Se-ZGTP-I has a therapeutic potential to intervene and prevent keloid formation and other fibrotic diseases.
Keywords: Collagen; Keloid; NG2; TGF-β1; Ziyang green tea polysaccharides.