Expression Of Insulin-like Growth Factor Binding Proteins-3 In Keloid And Its Role In Regulation Of Fibroblasts Proliferation And Collagen Biosynthesis

Objective: To investigate the expression of IGFBP-3 in keloids and its role in regulation of KFb proliferation and collagen biosynthesis. Methods :The immunohistochemistry method was used to detect the expression of IGFBP-3 in keloid lesions. The ELISA technique was used to assay the concentration of IGFBP-3 in conditioned-medium of KFb. The expression of IGFBP-3 mRNA in the keloid lesion and KFb were detected by using semiquantitative RT-PCR analysis. The ELISA technique was used to determine the effect of TGF- β on the production of IGFBP-3 by KFb. The effect of IGFBP-3 on proliferation of KFb were determined using the MTT assay. The potential of IGFBP-3 to stimulate collagen synthesis in the KFb were determined using the method of 3H proline marked technique. Results: Immunohistochemistry of paraffin sections from keloid lesions demonstrated increased staining in fibroblost cell and extracellular matrix. ELISA result show that KFb accumulated significantly more IGFBP-3 into conditioned-medium. RT-PCR analysis shows the mean leavels of IGFBP-3 mRNA expression in keloid lesions and KFb was significantly increased. ELISA result show that TGF-β1 caused statistically significant increases in the levels of IGFBP-3 in conditioned-medium from KFb. The result of the MTT assay show that IGFBP-3 enhance the proliferation of KFb. The result of the incorporation of [3H]proline into collagen assay show that IGFBP-3 caused statistically significant increases in the collagen synthesis of KFb .Conclusions: The expression of IGFBP-3mRNA and protein in keloid lesion and KFb were at high level compared with normal skin and normal fibroblasts. TGF-β1 increases the production of IGFBP-3 by KFb. IGFBP-3 enhance the proliferation of KFb and increase the collagen protein secretion. These findings suggest that IGFBP-3 may play a important role in the pathogenesis of keloids. Further study on the role of IGFBP-3 in keloids may be useful for us to deeply comprehend the pathogenesis of keloids and to find new methods for treating the disease.