[Expression and meaning of pro-angiogenic factors in retinopathy of diabetic rats]

To detect the expression of vascular endotheilal growth factor (VEGF), stromal cell-derived factor-1alpha (SDF-1alpha), and its receptor CXCR-4 in the retinopathy of diabetic rats, and to explore the relationship between those factors and diabetic-retinopathy (DR).

Diabetes was induced in 40 rats with a single intraperitional injection of streptozotocin(STZ). Experimental rats were randomly divided into M1 (diabetic for 1 month), M3 (diabetic for 3 months), and M5 (diabetic for 5 months) groups, and another 10 rats served as a normal control group (NC). Retinal vascular status was observed by transmission electron microscope. After retinal stretched preparation, VEGF, SDF-1alpha and CXCR-4 immunohistochemistry were done. Retinal VEGF, SDF-1alpha, and CXCR-4 mRNA were detected by semi-quantitative RT-PCR. Protein expression was measured by Western blot.

Under transmission electron microscope, change in vascular status was found in M1 to M5 groups, but not in the NC group. The changes became increasingly serious with the prolongation of the disease. By immunohistochemistry, we found the expression of VEGF, SDF-1alpha, and CXCR-4 on the retina increased gradually. It increased after injecting STZ for 1 month and increased significantly after 5 months. VEGF, SDF-1alpha, and CXCR-4 mRNA expression increased obviously after injecting STZ for 1 month and increased significantly after 5 months. Western blot showed that protein of VEGF, SDF-1alpha, and CXCR-4 had no change after injecting STZ for 1 month. It began to increase in the M3 group and increased most in the M5 group.

The expression of VEGF, SDF-1alpha, and CXCR-4 on the retina in retinopathy of diabetic rats increases gradually with the prolongation of the disease. It is an important factor for diabetic retinopathy.