PURPOSE: To evaluate the expression of the Na(+)-K(+)-2Cl(-)-cotransporter 2 (NKCC2) in the ischemic rat retina. METHODS: Retinal ischemia was induced by pressures 90 to 120 mmHg, above systemic systolic pressure. Immunohistochemistry and western blot analysis were performed. RESULTS: NKCC2 is expressed in the normal retina and its expression is increased by ischemia caused by intraocular pressure elevation. NKCC2 immunoreactivity was observed mainly in axon bundles of ganglion cells and horizontal cell processes in the retina. NKCC2 expression continuously increased with a peak value 3 days (to 415% of normal levels) after ischemic injury, and then gradually decreased to 314% of controls until 2 weeks post injury. The mean density of NKCC2-labeled ganglion cells per mm2 changed from 1,255 +/- 109 in normal retinas to 391 +/- 49 and 185 +/- 37 at 3 days and 2 weeks after ischemia, respectively (p < 0.05), implying cell death of ganglion cells labeled with NKCC2. CONCLUSIONS: Taken together, these results suggest that NKCC2, which is expressed in retinal ganglion and horizontal cells, may contribute to cell death by ischemic injury in the retina, although the molecular mechanisms involved remain to be clarified.
Animals ; Blotting, Western ; Disease Models, Animal ; Immunohistochemistry ; Intraocular Pressure ; Ischemia/etiology/*metabolism ; Male ; Microscopy, Confocal ; Ocular Hypertension/*complications/metabolism/physiopathology ; Rats ; Rats, Sprague-Dawley ; Retinal Diseases/etiology/*metabolism ; Retinal Ganglion Cells/*metabolism/pathology ; Sodium-Potassium-Chloride Symporters/*biosynthesis

The effects of the balance changes of pigment epithelium growth factor (PEDF) and vascular endothelial growth factor (VEGF) in whole-body and retinal tissue on rats with oxygen-induced retinopathy were investigated. Forty-eight neonatal SD rats at the age of 7 days were randomly divided into 4 groups. The neonatal rats in experimental groups were exposed to 75% to 80% oxygen for 5 days and then to normal air, and those in control groups were kept feeding in normal air. At the age of 17 and 22 days, all the neonatal rats received retina angiography with FITC-dextran and the pathological changes of retinal vessels and perfusion were observed. HE staining of the tissue section and the number counting of endothelial cells extending beyond the inner limiting membrane were performed to evaluate the endothelial proliferation. Immunohistochemistry was applied to detect the expression of PEDF and VEGF in retinal tissue, and ELISA to detect their expression in serum. A hypoxic-ischemic proliferation of retina and more endothelial cells extending beyond the inner limiting membrane were found in the neonatal rats in both experimental groups of 17-day old and 22-day old as compared with those in control group with the difference being statistically significant (P<0.01). VEGF staining of the rats in the 17-day old experimental group was significantly stronger, with an increasing positive rate, than that of the rats in the 17-day old control group (P<0.01). PEDF staining of the rats of 22 days old was weaker than that of the rats of 17 days old in the experimental groups (P<0.01). There was no significant difference in serum VEGF concentration among all groups (P>0.05). The serum PEDF concentration in the rats of 17 days old in experimental group was decreased significantly as compared with that in the rats of 17 days old in control group (P<0.01), and in experimental groups, the serum PEDF concentration of the rats of 22 days old was increased as compared with that of the rats of 17 days old (P<0.01). In conclusion, the obviously decreased serum PEDF concentration and the abnormal enhanced expression of VEGF density in local retinal tissue broke down the balance of PEDF/VEGF in whole-body or local tissues, which might play an important role in retinal vascular proliferation.
Animals ; Eye Proteins ; blood ; metabolism ; Nerve Growth Factors ; blood ; metabolism ; Oxygen ; adverse effects ; Rats ; Rats, Sprague-Dawley ; Retina ; metabolism ; Retinal Diseases ; etiology ; metabolism ; Serpins ; blood ; metabolism ; Time and Motion Studies ; Vascular Endothelial Growth Factor A ; blood ; metabolism

OBJECTIVETo investigate the neuroprotective effect of human brain-derived neurotrophic factor gene transfection into rabbit retina against acute high intraocular pressure (HIOP).

METHODSAcute HIPO was induced in one eye of 24 white rabbits via saline perfusion into the anterior chamber (model group), and the contralateral eye without treatment served as the control group. In another 24 rabbits, 10 microl recombinant adeno-associated virus (rAAV) vector containing human BDNF gene (rAAV-BDNF) was injected into the vitreous body of one of the eyes 3 days before the operation for HIPO (BDNF group). At 1, 3, 7, and 14 days after HIOP model establishment, 6 eyes in each group were excised to observe the number of retinal ganglion cells (RGCs) and the thickness of the inner retina layer. For the eyes dissected on day 14, electroretinogram b (ERG-b) wave was detected 30 min before (baseline) and on days 1, 3, 7 and 14 after HIOP. Another 5 rabbits were used for ultrastructural observation of the RGCs using transmission electron microscopy, including 1 without treatment, 2 with unilateral HIOP and 2 with rAAV-BDNF transfection before HIOP.

RESULTSThe amplitude of ERG-b wave showed no significant difference between the 3 groups before HIOP (P>0.05). In HIOP model group and BDNF group, the amplitude decreased to the lowest at 1 day after HIOP and failed to recover the baseline level at 14 days (P<0.01); at the end of the observation, the amplitude was significantly higher in BDNF group than in the model group (P<0.01). Decreased number of RGCs and thickness of inner retina layer occurred in the model group, but these changes were milder in BDNF group (P<0.05, P<0.01). Electron microscopy revealed ultrastructural changes in the RGCs following acute HIOP, and transfection with rAAV-BDNF ameliorated these changes.

CONCLUSIONrAAV-BDNF transfection protects the retinal structure and improves the amplitude of ERG-b wave after acute high IOP suggesting its neuroprotective effects.

Animals ; Brain-Derived Neurotrophic Factor ; biosynthesis ; genetics ; Dependovirus ; genetics ; metabolism ; Genetic Therapy ; methods ; Genetic Vectors ; genetics ; Humans ; Ocular Hypertension ; complications ; therapy ; Rabbits ; Retina ; pathology ; Retinal Diseases ; etiology ; prevention & control ; Transfection

The effects of black rice anthocyanidins (BRACs) on retinal damage induced by photochemical stress are not well known. In the present study, Sprague-Dawley rats were fed AIN-93M for 1 week, after which 80 rats were randomly divided into two groups and treated with (n = 40) or without BRACs (n = 40) for 15 days, respectively. After treatment, both groups were exposed to fluorescent light (3,000 +/- 200 lux; 25degrees C), and the protective effect of dietary BRACs were evaluated afterwards. Our results showed that dietary BRACs effectively prevented retinal photochemical damage and inhibited the retinal cells apoptosis induced by fluorescent light (p < 0.05). Moreover, dietary BRACs inhibited expression of AP-1 (c-fos/c-jun subunits), up-regulated NF-kappaB (p65) expression and phosphorylation of IkappaB-alpha, and decreased Caspase-1 expression (p < 0.05). These results suggest that BRACs improve retinal damage produced by photochemical stress in rats via AP-1/NF-kappaB/Caspase-1 apoptotic mechanisms.
Animal Feed/analysis ; Animals ; Anthocyanins/administration & dosage/*pharmacology ; Antioxidants/administration & dosage/*physiology ; Blotting, Western ; Caspase 1/*genetics/metabolism ; Diet ; Dietary Supplements/analysis ; I-kappa B Proteins/genetics/metabolism ; NF-kappa B/*genetics/metabolism ; Neoplasm Proteins/genetics/metabolism ; Nucleocytoplasmic Transport Proteins/genetics/metabolism ; Oryza sativa/chemistry ; Proto-Oncogene Proteins c-fos/genetics/metabolism ; Proto-Oncogene Proteins c-jun/genetics/metabolism ; Rats ; Rats, Sprague-Dawley ; Real-Time Polymerase Chain Reaction ; Retinal Diseases/etiology/*prevention & control ; Signal Transduction/*drug effects/radiation effects ; Transcription Factor AP-1/*genetics/metabolism