Protective Effect of Heat Shock Protein 70 Against Oxidative Stresses in Human Corneal Fibroblasts

We evaluated DNA protection effect of heat shock protein (HSP) against cytotoxic effects of exogenous nitric oxide (NO) and reactive oxygen intermediate (ROI). Cultured human corneal fibroblasts were divided into 4 groups. Control (Group I) was not exposed to a sub-lethal heat treatment. Other 3 groups were exposed to 43 degrees C for 1 hr, then incubated at 37 degrees C during different duration (1, 6, 24 hr, Group II, III, IV, respectively). Expression pattern of HSP 70 was analyzed by Western blot. Cell viability was measured by MTT assay and the relationship between HSP 70 expression and DNA damage was examined by terminal deoxyribonucleotidyl transferase mediated dUTP-digoxigenin nick and labeling (TUNEL) stain and single cell gel electrophoresis. Expression pattern of HSP 70 was dependent on recovery times. Cell viability following heat treatment was significantly increased and the TUNEL positive cell number was decreased at 6 hr. In single cell gel electrophoresis, tail moments were increased in a dose-dependent manner by SNAP and X/XO. Following heat treatment, tail moments showed decreased significantly at 6 hr. These results suggest that induction of HSP 70 by sub-lethal heat treatment is closely related with cytoprotective effects against oxidative stresses in human corneal fibroblasts.

Expression of Vascular Endothelial Growth Factor after Laser Induced Retinal Vein Occlusion in the Rat Eye

PURPOSE: To examine the effects of retinal vein occlusion (RVO) on VEGF expression and the ultrastructural change of the various ocular tissues in the rat. METHODS: Sprauge Dawley rats were grouped into RVO group induced with argon laser (n=30) and control (n=10). The ocular tissues of the rats were collected on the first, third and seventh day after RVO. VEGF expression was evaluated with immunohistochemical stain, and the ultrastructural changes were observed with electron microscopy. RESULTS: In control group, VEGF stain was positive in various ocular tissues except outer nuclear cells. In RVO group, VEGF expression had gradual increase in the inner nuclear layer, the retinal pigment epithelia and the ciliary body epithelia after RVO. Especially, in the retinal pigment epithelia, VEGF was significantly increased on the seventh day. In electron microscopic examination, degenerative changes had gradual increase in the inner and middle retinal layers after RVO. The degenerative changes in the retinal pigment epithelia were noted on the third day, and in the retinal photoreceptor cells on the seventh day. CONCLUSIONS: These results showed that VEGF expressions in the inner nuclear layer, retinal pigment epithelia and ciliary body epithelia had a gradual increase, and the ischemic damages of the retina and the optic nerve progressed from the inner layer to the outer layer after RVO.

Vitreous Vascular Endothelial Growth Factor Concentration In Various Vitreoretinal Disorders

PURPOSE: Vascular endothelial growth factor (VEGF) has been identified as an endothelial cell-specific angiogenic factor of intraocular neovascularization, a pathologic complication of many vitreoretinal disorders. We studied to evaluate clinical correlation of intravitreal VEGF concentration and various vitreoretinal disorders. METHODS: Forty eight vitreous fluid samples were obtained at the time of vitreoretinal surgery from 43 patients of various disorders. Concentrations of VEGF1 6 5 in vitreous fluid were determined by Human VEGF ELISA kit and its correlation with diabetes, intraocular hemorrhage, neovascularization, proliferative vitreoretinopathy, retinal detachment, pan retinal photocoagulation, and postoperative condition was statistically analyzed. RESULTS: Intravitreal concentrations of VEGF in case of intraocular hemorrhage (0.809+/-1.467 ng/ml), neovascularization (1.167+/-1.656 ng/ml), and anterior segment neovascularization (2.381+/-2.043 ng/ml) were significantly high (P<0.05). CONCLUSIONS: VEGF plays a major role in the development of neovascularization in the various retinal disorders.

A Case of Amniotic Membrane Transplanation for Late Onset Bleb-Related Endophthalmitis

Endophthalmitis is a severe and unfortunate complication after glaucoma filtering surgery which may present months to years after the initial surgical intervention. Amniotic membrane is immunologically inert and has antiadhesive and wound-protectioning effects. Furthermore, it reduces pain and helps epithelization. So several reports disclosed the uses of amniotic membrane in transplantation for reconstruction of various ocular surface diseases recently. We report the usefulness of antibiotics-soaked amniotic membrane transplatation for endophthalmitis with bleb rupture 4 years after trabeculectomy.

Ultrastructural Changes of Corneal Edema in Endotoxin-induced Uveitis Model

It has been well known that Nitrogen Oxide (NO)plays an important role in endotoxin-induced uveitis (EIU)model,but there has been few researches on development of corneal toxicity in this model. This study was planned to elucidate ultrastructural changes of corneal opacities and edema in EIU model. Lewis rats were separated into 3 groups:A,B and ontrol. Lipopolysaccharide(LPS)was administered subcutaneously into footpads in group A and B for induction of uveitis, while balanced salt solution was injected into those in control rats. NG-nitro-L-arginine methyl ester (L-NAME), known as inhibitor of NO synthase, was applied topically into eyes in group B before and after injection of LPS, respectively. 24 hours after injection of LPS, all of these eyes were observed with light microscope and electron microscope to assess severity of uveitis and corneal status. More severe corneal edema and opacity,along with more intense uveitis were noted in group A than in group B. Corneal thickness was 93.21 +/-8 .9 4 micrometerin control group,161.97+/-11.93micrometerin A group,and 121.67+/-11.35micrometerin B group.The rats treated with L-NAME showed less corneal edema,which was statistically significant(p<0.05). Ultrastructural alterations observed were as folloews: vacuolated necrosis in epithelium;increased perikeratocyte space, derangement of collagen fibrils due to stromal edema;and condensed chromatin,mitochondrial swelling, increased intercellular space in endothelium. Atypical pyknotic pattern of cellular necrosis due to intranuclear and perinuclear vacuoles was charactreristic. However, ultrastructures were relatively well preserved in group B except for intracytoplasmic vacuoles.These results suggest that L-NAME inhibits corneal toxicity caused by endotoxin. In conclusion,this study support the hypothesis that NO plays an important role in corneal toxicity.