Study on vascular endothelial growth factor and its receptor in the vitreous of diabetic rats

To investigate the vitreous level of vascular endothelial growth factor (VEGF) and kinase insert domain-containing receptor (KDR) in diabetic rats, and to explore the role of VEGF and KDR in diabetic retinopathy.

Eighty-four adult Wistar rats were randomly divided into two groups. Fifty-eight rats in group A were injected intraperitoneally with streptozotocin to induce diabetes and 20 rats in group B were injected with physiological saline. Blood glucose meter was used to detect the blood glucose level at 72 hours after injection; blood glucose level ≥ 16.67 mmol/L was considered to be successful modelling. Blood glucose level was assayed and body mass was measured on the same modelling day, one week, two weeks and four weeks after modelling. Four weeks after modelling, the vitreous was taken, and the VEGF and KDR levels were detected by enzyme-linked immunosorbent assay (ELISA). The eyeballs were fixed with paraform and embedded by petrolin for haematoxylin and eosin (H and E) staining.

Forty-two rats survived and 16 rats died in group A. No rats died in group B. The blood glucose at one week, two weeks and four weeks between the two groups had statistical differences (p < 0.05). The weight at one week and two weeks between the two groups was not different but there was statistical difference at four weeks between the two groups (p < 0.01). The ELISA results showed that the VEGF and KDR levels were 0.276 ± 0.026 ng/mL and 2.936 ± 0.295 ng/mL in group A, 0.231 ± 0.021 ng/mL and 2.394 ± 0.227 ng/mL in group B, respectively. The VEGF and KDR levels of group A were higher than those of group B (p < 0.05).

The changes of VEGF and KDR levels in the vitreous of diabetic rats were related to the early retinopathy induced by diabetes.