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

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 (1x107/5 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.