Gene expression analysis of oxidative stress and apoptosis in proton-irradiated rat retina

• Published in: In vivo (Athens) Vol. 24; no. 4; pp. 425 - 430
• Main Authors: Mao, Xiao W, Green, Lora M, Mekonnen, Tsehay, Lindsey, Nathan, Gridley, Daila S
• Format: Journal Article
• Language: English
• Published: Greece 01-07-2010
• Subjects: Animals; Apoptosis - radiation effects; DNA, Complementary - genetics; DNA, Complementary - radiation effects; Dose-Response Relationship, Radiation; Euthanasia; Gene Expression - radiation effects; In Situ Nick-End Labeling; Male; Oxidative Stress - radiation effects; Polymerase Chain Reaction; Protons - adverse effects; Rats; Rats, Sprague-Dawley; Retina - physiology; Retina - radiation effects; RNA - genetics; RNA - radiation effects; Up-Regulation - radiation effects
• ISSN: 0258-851X

The aim of this study was to examine the induction of oxidative stress and apoptosis-associated gene expression profiles in retina after proton irradiation exposure at 0.5 to 4 Gy.
One eye of each Sprague-Dawley rat (6 per group) was irradiated with a conformal proton beam to total doses of 0, 0.5, 1 and 4 Gy. Retinal tissues were isolated for characterization of gene expression profiles 6 hours after proton radiation.
For oxidative stress, many genes responsible for regulating the production of reactive oxygen species (ROS) were significantly up-regulated (Fmo2, Gpx2, Noxa1 and Sod3) compared to controls. Several important genes involved in the initiation or activation of apoptotic signaling pathways were significantly up-regulated following irradiation (Fas, Faslg, Trp63 and Trp73). TUNEL assay and caspase-3 immunocytochemical analysis revealed increased apoptotic immunoreactivity following irradiation.
The data revealed that exposure to proton radiation induced oxidative stress-associated apoptosis. In response to ionizing radiation, the expression of genes involved in pathways mediating apoptosis may be differentially regulated in different dose regimens.