PURPOSE: To identify altered patterns of retinal mRNA expression in a rat model of oxygen-induced retinopathy (OIR). METHODS: Sprague-Dawley rats from P2 to P14 were exposed to hyperoxia (80% oxygen) to induce OIR and then returned to normoxic conditions. Control rats were sustained in room air. Retinal gene expression between the rats of OIR and the controls was compared using cDNA microarray analysis. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to verify the microarray results. RESULTS: Among a total of 12,731 cDNAs analyzed by mircroarray, 13 genes were strongly up- or down-regulated (>2-fold change over controls) in the OIR rats. We found a significant increase in expression of 10 genes (CaM-kinase II inhibitor; acidic nuclear phosphoprotein 32 family, member A; vascular endothelial growth factor; interferon alpha-inducible protein 27-like; similar to enthoprotin, epsin 4, clathrin interacting protein; nidogen [entactin]; tubulin, beta5; fibrillin-1; spectrin beta2; and stearoyl-coenzyme A desaturase 2) and a significant decrease in expression of 3 genes (myelin-associated oligodendrocytic basic protein, heat shock protein, and decorin) in OIR rats compared to controls. CONCLUSIONS: We confirmed changes in expressions of various retinal genes in a rat model of OIR by microarray and RT-PCR. This study should contribute to the understanding of genetic indicators associeated with OIR.
Animals ; Animals, Newborn ; Down-Regulation ; Gene Expression ; Microarray Analysis ; *Oxygen ; RNA, Messenger/*metabolism ; Rats ; Rats, Sprague-Dawley ; Retina/*metabolism ; Retinal Diseases/*chemically induced/*metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Up-Regulation

OBJECTIVETo observe the changes of nuclear factor-kappa B (NF-kappaB) in the course of N-methyl-N-nitrosourea (MNU)-induced apoptosis of rat retinal photoreceptor cells and investigate the mechanism of MNU-induced retinal damage.

METHODSA single intraperitoneal injection of 60 mg/kg MNU was given to 50-day-old female rats, which were sacrificed at different intervals after MNU treatment. The retinal damage was examined with optical microscopy and photoreceptor cell apoptosis detected by TUNEL assay. Western blotting was performed to analyze the changes in NF-kappaB.

RESULTSPyknosis of the photoreceptor cell nuclei and disorientation of the outer segment of the photoreceptor layer was observed 24 h after MNU treatment, and the outer nuclear layer and photoreceptor layer were almost completely lost on day 7. Photoreceptor cell apoptosis peaked at 24 h, and in the apoptotic cascade, NF-kappaB p65 protein was only detected 12 and 24 h after MNU treatment, whereas the amount of I kappa B alpha, in contrast, markedly increased in the cytoplasm as well as in the nuclei.

CONCLUSIONMNU-induced retinal damage might be mediated through the signaling pathway of NF-kappaB/I kappa B alpha.

Animals ; Apoptosis ; drug effects ; Blotting, Western ; Female ; I-kappa B Proteins ; metabolism ; In Situ Nick-End Labeling ; Methylnitrosourea ; toxicity ; NF-kappa B ; metabolism ; Rats ; Rats, Sprague-Dawley ; Retinal Diseases ; chemically induced ; metabolism ; pathology

PURPOSE: We investigated whether oxygen-induced retinopathy (OIR) results in changes in the protein expression of neuronal and inducible nitric oxide synthases (nNOS and iNOS, respectively) in rat model of OIR. In addition, we evaluated whether treatment of rats with triamcinolone acetonide (TA) prevents this response. METHODS: To promote OIR, Sprague-Dawley rats were exposed to hyperoxia from postnatal day 2 (P2) to P14. They were then returned to normoxia after P15. TA was injected into the right vitreous of P15 rats, while saline was injected into the left vitreous. At P18 the expression of nNOS and iNOS was determined using Western blotting and immunostaining techniques in retinas obtained from control rats. RESULTS: In P18 OIR rats, the abundance of nNOS and iNOS protein was significantly increased compared with controls. These increases were not observed in the retinas of rats treated with TA. The change in expression of nNOS and iNOS were specific to parvalbumin and glial fibrillary acidic protein-positive cells. Treatment with TA prevented the increased expression of nNOS and iNOS in all samples. CONCLUSIONS: Hypoxia upregulates expression of nNOS and iNOS in OIR rat retinas, which is can be prevented by treatment with TA.
Animals ; Animals, Newborn ; Anoxia/metabolism/pathology/*prevention & control ; Blotting, Western ; Disease Models, Animal ; Female ; Glucocorticoids/pharmacology ; Immunohistochemistry ; Neurons/metabolism ; Nitric Oxide Synthase Type II/*biosynthesis ; Oxygen/toxicity ; Pregnancy ; *Pregnancy, Animal ; Rats ; Rats, Sprague-Dawley ; Retina/*metabolism/pathology ; Retinal Diseases/chemically induced/pathology/*prevention & control ; Triamcinolone Acetonide/*pharmacology