Effects of thalidomide in retinal ischemia-reperfusion injury

2.ABSTRACT EFFECTS OF THALIDOMIDE IN RETINAL ISCHEMİA-REPERFUSİON INJURY This study was performed in the Ophthalmology Department of Fırat University Medical School. The purpose of this study was to determine the protective effect of thalidomide in guinea pig retina that was exposed to ischemia-reperfusion injury. Twenty-one male albino guinea pigs weighing 400-550 g were enrolled in the study and they were divided into 3 groups each having randomly selected 7 guinea pigs. In Group 1 (Placebo/nonischemic group) no ischemia-reperfusion was induced. In group 2 (Sham group) ischemia-reperfusion was induced and saline was adrninistered as placebo. In group 3 (Thalidomide group) both ischemia-reperfusion was induced and thalidomide was administered. Both eyes of each guinea pig were studied and one eye was used for biochemical assay and the other for pathological evaluation. We induced anesthesia and analgesia in all guinea pigs except for the placebo group. Then retinal ischemia was induced in group 2 and 3 by increasing the intraocular pressure to 150 mmHg for 90 minutes. We have administered 300 mg/kg oral thalidomide in group 3, 24 hours before the onset of ischemia. After 90 minutes of ischemia, intraocular pressure decreased to normal values and reperfusion was induced for 6 days. Thalidomide group was administered oral 300 mg/kg talidomide every 24 hours during the reperfusion period. After 6 days the eyes were enucleated. The mean retinal tissue values of VEGF and TNF-a in the sham group were statistically higher than those of the plasebo group (p=0.002, p=0.002). The mean retinal tissue values of VEGF and TNF-a in thalidomide treated group were observedto be significantly lower than those of the sham group (p=0.002, p=0.009). The mean retinal tissue value of endostatin in the sham group was not statistically higher than that of the plasebo group (p=0.08). The mean retinal tissue value of endostatin in the thalidomide group was statistically higher than plasebo group (p=0.009), but was not statistically higher than that of the sham group (p=0.1). Histopathologic analysis of each group indicated that thalidomide group had not significantly (p=0.08) protective effect in the inner plexiform layer of retina. But also histopathologic analysis of each group indicated that thalidomide group had statistically significant (p=0.004) protective effect in the inner layers of retina (internal limitan membran and inner plexiform layers) by preventing PNL infiltration in these layers. Our results suggest that according to retinal VEGF, TNF-a levels and histopathological changes in eyes those were induced to ischemia-reperfusion, thalidomide have protective role by decreasing retinal VEGF, TNF-a levels and preventing PNL infiltration in the inner retinal layers of retina. Key words: Thalidomide, ischemia-reperfusion, retina.