RESUMO
AIMS: To define whether 1,25-dihydroxy vitamin D3 (1,25-(OH)2 D3) can protect diabetic retinopathy and to investigate its impact on the expressions of vascular endothelial growth factor (VEGF) and transforming growth factor-ß1 (TGF-ß1) in the retinas of rats with diabetes. METHODS: Male Sprague-Dawley (SD) rats were divided into normal control group, 1,25-(OH)2 D3 group and diabetes group. The rats in 1,25-(OH)2 D3 group and diabetes group were established to type 2 diabetes model with high-fat and high-sugar diet and streptozotocin (STZ). Meanwhile, the rats of 1,25-(OH)2 D3 group were treated with 1,25-(OH)2 D3. After 13 weeks, morphological changes of retinal tissues were observed under microscopes after hematoxylin-eosin staining. VEGF and TGF-ß1 expressions in the retinal tissues were detected with immunohistochemistry staining. RESULTS: Pathological examination showed an appearance of edema and disordered arrangement of retinal tissues in diabetes group, but milder pathological changes in 1,25-(OH)2 D3 group. VEGF and TGF-ß1 expressions of both diabetes group and 1,25-(OH)2 D3 group significantly increased (P<0.05), but those of 1,25-(OH)2 D3 group were significantly lower than diabetes group (P<0.05). CONCLUSION: 1,25-(OH)2 D3 had partially protective effect on diabetic retinopathy of diabetic rats, the mechanism of which might inhibit VEGF and TGF-ß1 expressions in the retinal tissues.