Effects of steroids, interferon-2B, or interluekin 1B on apoptosis of fibroblasts from keloid, hypertrophic scars, and normal skin and related signal pathway

Abstract

Wound healing can lead to hypertrophic scar or keloid formation, characterized by an overabundant extracellular matrix. Current established treatment strategies include surgical resection, triamcinolone steroid injection, pressure therapy, silicone therapy, radiotherapy, etc. Cytokines also play a critical role in the regulation of cellular activities and extracellular matrix metabolism. Interferons (IFN) represent a group of antifibroproliferative agents that inhibit fibroblast proliferation and collagen production, and interleukin (IL)-1β also accelerates hypertrophic scar fibroblasts to produce collagenolytic enzymes, leading to tissue destruction. This study addressed the effects of steroid, IFN α-2b, or IL-1β on apoptosis and cell pathway of fibroblasts from keloids, hypertrophic scars, and normal skins and different responses of different fibroblasts. Six samples of keloid, six samples of hypertrophic scar, and six samples of normal skin were, respectively, collected from patients, and fibroblasts from different sources were cultured in vitro. After different fibroblasts were treated with dexamethasone (0.1 mg/ml) or IFN α-2b (1,000 μ/ml) or IL-1β (200 μ/ml), Bax and Bcl-2 were detected in situ by immunohistochemical staining; deoxyribonucleic acid ladders of different fibroblasts were observed by gel electrophoresis, and relative activated (phospho-) extracellular-signal-regulated kinase (ERK) 1/2 and c-Jun N-terminal kinase (JNK) pathways were detected by the method of fast activated cell-based enzyme-linked immunosorbent assay. In media containing dexamethasone, apoptosis took place in fibroblasts from keloids, hypertrophic scars, and normal skins by gel electrophoresis with increased rate of Bax/Bcl-2. Activated (phospho-) ERK1/2 and activated (phospho-) JNK expressions increased in three different fibroblasts. In media containing IFN α-2b, no apoptosis took place in three different fibroblasts without any change of expressions of Bax and Bcl-2 except for the expression of decreased Bcl-2 in fibroblasts from keloids. Activated (phospho-) ERK1/2 expression decreased in fibroblasts from keloid and hypertrophic scars without any changes of activated (phospho-) JNK expression, and IFN α-2b did not affect both activated (phospho-) ERK1/2 and activated (phospho-) JNK expressions in fibroblasts from normal skin. In media containing IL-1β, apoptosis of fibroblasts from keloids was induced by stimulating activated (phospho-) ERK1/2 and activated (phospho-) JNK pathways; IL-1β could not induce apoptosis of fibroblasts from normal skin (radio of Bax/Bcl-2 decreasing) whose activated (phospho-) ERK1/2 pathway was stimulated without any changes of activated (phospho-) JNK expression. Apoptosis in fibroblasts from hypertrophic scars was induced by activating the JNK pathway and prohibiting the ERK1/2 pathway. The effects of steroid, IFN α-2b, or IL-1β on apoptosis of different fibroblasts were different through different cell signal pathways, although all of them were effective for treatment of abnormal scars.