Promoting effects of insulin-like growth factor-1 on proliferation of orbital fibroblasts derived from thyroid associated ophthalmopathy

Abstract

Background Thyroid associated ophthalmopathy (TAO) is an autoimmune disease.Current research on the pathogenesis focuses on common autoantigen.Insulin-like growth factor-1 receptor (IGF-1R) is necessary for the function of IGF-1 , also IGF-1 plays an important role in signaling pathway of thyroid stimulating hormone receptor (TSHR). Objective This study was to investigate the effects of IGF-1 on the proliferation, expression of IGF-1R and TSHR on cultured orbital fibroblasts (OFs) derived from TAO. Methods Human orbital tissue was obtained from 17 TAO patients who received orbital adipectomy and 4 normal controls who received cosmetic surgery in West China Hospital from March 2016 to June 2016.OFs were cultured by explant culture with DMEM/F12 containing 5% fetal bovine serum and identified by immunochemistry.The OFs were treated with different concentrations of IGF-1.IGF-1 at different concentrations (0, 50, 100, 125 μg/L) was added into the medium, respectively, and the proliferation of the cells (absorbancy) was detected by MTS.The percentages of IGF-1R and TSHR expressions in the cells were assayed by flow cytometry. Results Cultured cells appeared to be spindle-like in shape and grew well with abundant cytoplasm.The characteristics of the cells derived from TAO patients were consistant with normal ones.The cells showed the positive response for vimentin and absent respose for desmin, S-100, myoglobin and cytokeratin.The proliferative values of OFs were gradually elevated with the increase of IGF-1 dose in both TAO group and normal group (Fgroup =219.639, P 0.05; Fconcentration= 0.004, P>0.05). Conclusions IGF-1 can promote the proliferation of OFs and up-regulate the expression of IGF-1R in OFs.However, IGF-1 dose not play a regulating effect on the expression of TSHR in OFs. Key words: Thyroid associated ophthalmopathy; Fibroblasts, orbit/metabolisms; Insulin-like growth factor-1/metabolism; Receptor, insulin-like growth factor-1/metabolism; Receptors, thyrotropin/metabolism; Cell proliferation/drug effects; Cells, cultured