Studies On The Effects Of Preadipocyte Fibroblasts On The Pathogenesis Of Thyroid Associated Ophthalmopathy

Objectives: To investgate the effects of dexamethasone, insulin, IBMX, IL-6 and somatostatin in cultured orbital fibroblasts and preadipocytes from patients with thyroid associated ophthalmopathy (TAO) and normal control subjects. The changes of gene expressions were identitied after the preadipocytes differentiated. Expression of thyroid stimulating hormone receptor (TSHR) was studied in orbital tissue and cultured cells from TAO and normal control subjects.Methods: Orbital fibroblasts and preadipocytes obtained from 13 patients with TAO and 7 control subjects are primarily cultured, the ultrastructure of which is observed by transmission electron microscopy. The effects of dexamethasone, insulin, IBMX, IL-6 and somatostatin were compared on the preadipocyte differentiation. The expression of adhesion molecule was measured in cultured cells by flow cytometry. The changes of gene expressions were profiled after the differentiation of preadipocytes by SBC-R-HC-100 -20cDNA gene expression DNA microarrays. The expression of TSHR was identified in orbital tissue and cultured cells from TAO and normal control subjects by real-time PCR.Results: (1) The orbital fibroblasts and preadipocytes are successfully cultured, the preadipocytes were induced to differentiate into adipocytessuccessfully. The optimal concentrations of dexamethasone, insulin and IBMX are respectively O.lumol/L, lOug/ml and 0.25mmol/L. (2) IL-6 can not improve preadipocytes to transfer into adipocytes, not influence the expression of adhesion molecule. Somatostatin can suppress the differentiation of preadipocyte. (3) There were 279 pieces of genes altering expression on gene microarrays, with 126 showing up-regulation and 153 showing down-regulation. HMG1, CCND1, PDGFR, and so on, may participate in the controlling of preadipocyte differentiation. (4) The TSHR expressions of connective/muscle and fatty tissue of patients with TAO were detected, whereas the expressions of tissues from normal subjects were not detected. The quantities of TSHR expressions of fatty tissues were significantly higher than that of connective/muscle tissues. The quantities of TSHR expressions of cultured fibroblasts and preadipocytes of TAO were statistically the same, but the level of TSHR expression increased markedly after the preadipocytes were induced into adipocytes.Conclusions: There were no significant ultrastructural differences between the orbital fibroblasts and preadioocytes from patients and normal subjects, but there was difference of biological function, preadipocytes can differentiate into adipocytes. Many genes involved in the course of differentiation. TSHR in the orbital tissues and cultured cells of patients was detected, and the level of TSHR expressions in fatty tissue and adipocytes was higher. So, orbital preadipocytes may play a important role in the pathogenesis of TAO.