Expression of IGFBP­6 in proliferative vitreoretinopathy rat models and its effects on retinal pigment epithelial­J 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 insulin­like growth factor­binding protein­6 (IGFBP­6) in PVR using rat models and its effects on retinal pigment epithelial­J (RPE­J) cells. PVR Wistar rat models were administered intravitreal injection of RPE­J cells (1x106/5 µl) combined with platelet­rich plasma (1x107/5 µl). The concentration of IGFBP­6 in the vitreous and serum of rats was tested by an enzyme­linked immunosorbent assay and the expression of IGFBP­6 mRNA in the liver and retina of rats was determined by quantitative polymerase chain reaction (qPCR). The expression of IGFBP­6 mRNA in the RPE­J cells stimulated by vitreous or serum from PVR patients or normal volunteers was also determined by qPCR. The proliferation of RPE­J cells was evaluated by the 3­(4,5­dimethylthiazol­2­yl)­5­(3­carboxymethoxyphenyl)­2­(4­sulfophenyl)­2H­tetrazolium, inner salt (MTS) method. The success rate of PVR rat model induction at the 8th week was 89.5% (34/38). The concentration of IGFBP­6 in the vitreous and serum of PVR rats was significantly higher than that of the control group (P<0.05). The expression of IGFBP­6 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 IGFBP­6 mRNA in the RPE­J cells (P<0.05). IGFBP­6 only inhibited IGF­II­stimulated proliferation but not the basal level of proliferation or the PDGF/VEGF­stimulated RPE­J cell proliferation. Thus, the trends and effects of IGFBP­6 provide the possibility of PVR therapeutic targets, with the vitreous representing a significant environmental factor in the progression of PVR.