Expression of IGFBP-6 in proliferative vitreoretinopathy rat models and its effects on retinal pigment epithelial-J cells

Abstract

Proliferative vitreoretinopathy (PVR) is one of the most common causes for failed retinal detachment surgeries. The aim of the present study was to investigate the role of insulin-like growth factor-binding protein-6 (IGFBP-6) in PVR using rat models and its effects on retinal pigment epithelial-J (RPE-J) cells. PVR Wistar rat models were administered intravitreal injection of RPE-J cells (1x106/5 μl) combined with platelet-rich plasma (1x10 7/5 μl). The concentration of IGFBP-6 in the vitreous and serum of rats was tested by an enzyme-linked immunosorbent assay and the expression of IGFBP-6 mRNA in the liver and retina of rats was determined by quantitative polymerase chain reaction (qPCR). The expression of IGFBP-6 mRNA in the RPE-J cells stimulated by vitreous or serum from PVR patients or normal volunteers was also determined by qPCR. The proliferation of RPE-J cells was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl) -2H-tetrazolium, inner salt (MTS) method. The success rate of PVR rat model induction at the 8th week was 89.5% (34/38). The concentration of IGFBP-6 in the vitreous and serum of PVR rats was significantly higher than that of the control group (P<0.05). The expression of IGFBP-6 mRNA in the retina of PVR rats was also significantly higher compared with the control group (P<0.05). The vitreous from PVR patients and donors significantly stimulated the expression of IGFBP-6 mRNA in the RPE-J cells (P<0.05). IGFBP-6 only inhibited IGF-II-stimulated proliferation but not the basal level of proliferation or the PDGF/VEGF-stimulated RPE-J cell proliferation. Thus, the trends and effects of IGFBP-6 provide the possibility of PVR therapeutic targets, with the vitreous representing a significant environmental factor in the progression of PVR.