Insulin-like growth factor-1 induced activation and expression of signal transducers and activators of transcription-3 in scleral fibroblast of guinea pigs

Abstract

To investigate the expression of signal transducers and activators of transcription 3 (STAT3) in sclera fibroblast of guinea pigs for understanding whether STAT3 signaling transduction pathway induced by the insulin-like growth factor-1 (IGF-1) was constitutively activated. Immunocytochemical staining was used to determine the protein levels of STAT3 and P-STAT3 (activated STAT3) in scleral fibroblasts. RT-PCR was used to detect the mRNA of STAT3. The effects of IGF-1 on scleral fibroblast proliferation were measured by MTT assay. Immunocytochemical staining and RT-PCR revealed that STAT3 protein and mRNA were over-expressed in the cells which contained constitutively activated STAT3 signaling transduction pathway (t=-6.925, -10.179 and 9.363; P<0.001). The results of MTT showed that IGF-1 induced fibroblasts proliferation significantly at concentrations of 0.5, 1.0, 10.0 microg/L (P<0.05). STAT3 signaling transduction pathway is constitutively activated in the treated scleral cells by IGF-1, suggesting that STAT3 signaling transduction pathway may play a critical role in the occurrence of myopia and sclera remodeling.