Effects of interferon alpha 2B on corneal neovascularization

Objective: To investigate whether or not interferon-alpha 2b has an anti-vascular endothelial growth factor (anti-VEGF) effect on corneal neovascularization (CNV) detected by real time polymerase chain reaction (PCR) and immunohistochemical staining. Method: Thirty Wistar-Albino male rats were divided into three groups of ten rats each, and two corneas were obtained rom each rat. CNV was induced by application of silver nitrate to the corneas for all groups. In the first group 1 million IU/ml and in the second group 3 million IU/ml interferon-alfa 2b and in the control group isotonic saline was dropped to both eyes two times a day for two weeks after application of silver nitrate to the corneas. At the end of the study, rats were sacrificed by cervical dislocation under ether anesthesia and both of the corneas were removed. The right corneas were used for immunohistochemistry staining and the left ones were used for real time polymerase chain reaction. Results: Mitogen activated protein kinase-1 gene expression levels were detected significantly higher in both 1 million IU/ml and 3 million IU/ml groups compared to the control group (p = 0.014 and p = 0.008, respectively). Vascular endothelial growth factor receptor-2 gene expression levels were found to be significantly higher in 3 million IU/ml than the control group (p = 0.028). There was no difference between the control and 1 million IU/ml and between 1 million IU/ml and 3 million IU/ml groups for the vascular endothelial growth factor receptor-2 gene expression. Vascular endothelial growth factor-A gene expression levels were also detected significantly higher in 3 million IU/ml group than the control group and there was no difference between the control and 1 million IU/ml and between 1 million IU/ml and 3 million IU/ml groups at the vascular endothelial growth factor-A expression level (p≤0.05). At the extracellular signal regulated kinase gene expression levels, there was no difference between all groups (p = 0.545). Immunohistochemical staining was insufficient to compare all groups. Conclusion: At the end of the study, it has been shown that interferon-alfa 2b does not have anti-VEGF effects in the level of gene expression on CNV despite its known anti-VEGF activities. Varied results can be obtained by using different subject and different study periods. Key words: Corneal neovascularization, vascular endothelial growth factor, interferon-alfa 2b, real time polymerase chain reaction, immunohistochemistry.