Oxidative stress induces adult T cell leukemia derived factor/thioredoxin in the rat retina.

Background: Adult T cell leukemia derived factor (ADF), originally defined as an interleukin-2 receptor inducer, is a human thioredoxin homolog. ADF/thioredoxin has several biologic functions, such as defense against cellular damage, activity to scavenge oxidative stress by hydrogen peroxide radicals and cytokine-like properties. We hypothesized that under certain conditions, ischemia followed by reperfusion and/or light exposure, ADF may be induced in the retina.
Experimental Design: To test this hypothesis, we prepared experimental animal models in which oxidative stress could be applied to the retina. In the present study, we examined ADF expression in the rat retina using temporary ischemia and reperfusion, and photodynamic retinal vascular thrombosis by immunohistochemical and Western blotting methods.
Results: ADF expression was strongly induced in the retinal pigment epithelial cells after 2 hours of ischemia followed by 2, 24, or 48 hours of reperfusion. ADF was also expressed in retinal pigment epithelial cells as early as 3 hours after light exposure followed by rose bengal injection, and this expression increased with time. Western blotting data showed that ADF expression increased in the retinal pigment epithelial cells in the experimental group, as compared with the control group. These results indicate that ADF is actively induced in retinal pigment epithelial cells upon oxidative stress.
Conclusions: ADF induction in retinal pigment epithelial cells may be involved in the defense mechanism against cellular damage caused by active oxygen species generated during oxygen stress to the retina.