Effect of vascular endothelial growth factor on retinal ganglion cells of rats with chronic intraocular hypertension

Aim: To investigate the effect of vascular endothelial growth factor (VEGF) on the expression of pigment epithelium-derived factor (PEDF) in retina and the protective effect of VEGF on retinal ganglion cells (RGCs) of rats with chronic elevated intraocular pressure (EIOP) and it's potential mechanism. Methods: 30 females Sprague-Dawley rats were randomly divided into three groups: EIOP + VEGF group (A), EIOP + vehicle group (B) and sham operated + VEGF group (C). The EIOP was introduced by obstructing episcleral veins in Group A and Group B. In the Group C, only the bulber conjunctiva was opened without obstructing episcleral veins. Immediately after surgery, rats in the Group A and Group C were intravitreously injected with 2 mu L of VEGF. In the Group B, rats were intravitreously treated with 2 mu L of normal saline. At 3 and 14 days after injection, animals were sacrificed and the eyes were collected for preparation of frozen sections. Results: After surgery, the IOP increased significantly in the Group A and Group B. There was no significant difference in the IOP at day 3 and day 14 after operation. The PEDF expression in the Group A and Group B was higher than that in the Group C. TUNEL staining showed the apoptotic RGCs markedly reduced after VEGF treatment when compared with rats without treatment. Conclusion: Intravitreal treatment with VEGF may reduce the apoptosis of RGCs in rats with chronic intraocular hypertension.