Background: To profile the pattern of gene expression in diabetic rat retinas with or without intravitreal injection of erythropoietin.
Design: By using streptozotocin-induced diabetic rats, after intravitreal injection of erythropoietin, neurosensory retinas were collected to determine the effect of erythropoietin on gene expression.
Participants: Three groups of Sprague–Dawley rats were studied: normal control (15), diabetic rats with saline injection (15) and diabetic rats with intravitreal erythropoietin treatment (15).
Methods: Diabetes was induced by intra-peritoneal injection of streptozotocin. Intravitreal injection of erythropoietin was performed at the following time points: 0, 30 and 120 days after diabetes onset. Four days after each injection at above-mentioned time points, the retinas were harvested for microarray assay. The real-time PCR was used to evaluate the microarray data.
Results: Genes encoding inflammatory factors, such as interleukin-2 and interleukin-11, which were upregulated in the diabetic retinas, were restored after erythropoietin treatment. Genes encoding pro-apoptotic effectors, like Tnfrsf5, Bid3 and Bcl2l1, were also upregulated in diabetic rats and attenuated in erythropoietin-treated group. In addition, real-time PCR were employed to confirm the changes of the genes Trex2, G1P2, DHX58, RGD1311906 and LOC689064, which have not been reported in diabetic retinopathy.
Conclusions: Intravitreal erythropoietin treatment is able to normalize the gene expression responsible for pro-apoptotic and inflammatory responses noted in diabetic retinas.