Survivin contributes to the progression of diabetic retinopathy through HIF-1α pathway.

Hypoxia plays a critical role in the formation of diabetic retinopathy (DR). Hypoxia inducible factor-1α (HIF-1α) and survivin are upregulated following hypoxia, and contribute to the angiogenesis in cancer. The goal of our study was to investigate if the expression of HIF-1α and survivin is related to the retinal vascular change of rats with different stages of diabetes mellitus (DM). Wistar rats were randomly divided into DM for 1 month (DM1) group, DM3, DM6 group and normal control group. Streptozotocin (STZ) was used to induce diabetic rat models. Retinal vascular digest preparation was taken to observe the change of retinal microvessels. The expression of HIF-1α and survivin was determined by real-time PCR and Western blot. In DM3 group, capillaries became circuitous and irregular. Acellular capillary were detected in DM6 group. In the same time, the number of pericytes significantly decreased in DM3 and DM6 groups. The expressions of HIF-1α were more increased in the DM3 and DM6 groups. However, the expressions of survivin only were upregulated in DM6 group .These data suggest that HIF-1α induced the upregulation of survivin in the early stage of DR. Survivin contributed to the development and progression of DR through the HIF-1α pathway and become an important progression marker of DR.