Rat Glaucoma Research Articles

C-fos and c-jun expressions in nitric oxide synthase immunoreactive neurons in the lateral geniculate nucleus of experimental glaucomatous rats.

The present study was initiated to investigate the expressions of c-fos and c-jun in nitric oxide synthase immunoreactive neurons and their possible roles in the lateral geniculate nucleus (LGN) of glaucomatous rats. An experimental one-eye glaucoma model was created by cauterisation of the limbal-derived veins. Animals were killed by cardiac perfusion, and brains containing the LGN were removed and processed for c-fos, c-jun and neuronal nitric oxide synthase (nNOS) immunohistochemistry. No c-fos or c-jun immunoreactivity was observed in the LGN of control rats. In the glaucomatous rats, expression of c-fos and c-jun was induced bilaterally in the ventral LGN (vLGN) as early as 2 h postoperation. The number of c-fos-immunopositive cells increased at 1 and 2 days postoperation in both the lateral and medial subdivisions of the vLGN (vLGN-l and vLGN-m). Thereafter, the expression decreased and was totally absent at 1 and 2 weeks. No c-fos was induced in the dorsal LGN (dLGN). C-jun-immunopositive cells were mainly localised in the intergeniculate leaflet and vLGN. Few neurons were observed in the dLGN. The number of c-jun-immunopositive cells decreased at 1 and 2 weeks postoperation. Some of the c-fos- and c-jun-immunopositive cells were also nNOS immunopositive. The present results reveal that glaucoma activates the expressions of immediate early genes (IEGs) in some cells of the LGN. It is postulated that they may play important roles in the pathologic processes of glaucoma. The relationship between these IEGs and nitric oxide was also discussed.

Electroretinographic Abnormalities in a Rat Glaucoma Model with Chronic Elevated Intraocular Pressure

The purpose of this study was to determine the ability of electroretinographic (ERG) measurements to document progression of the retinopathy in a rat glaucoma model. Thirty four rats with a chronic intraocular pressure (IOP) elevation induced in one eye by cautery of three episcleral/extra-orbital veins were studied in four separate groups. ERGs were recorded sequentially in Group A rats (n=12) at baseline, and after approximately 20, 40 and 60 days of high IOP, and in three additional groups of rats (n=6 or 10 per group) after approximately 58, 30 and 175 days of high IOP, respectively. Scotopic ERG parameters recorded simultaneously from both eyes in Group A rats were: a- and b-wave amplitudes, implicit times, oscillatory potential amplitudes (OPs) determined at three different light-flash intensities, and the light-adapted (photopic) ERG b-wave amplitude. In the other groups of rats, only scotopic ERG a-wave, b-wave and OP amplitudes were measured.In Group A rats that were followed sequentially, all the ERG parameters recorded with attenuated stimuli showed significant time-dependent changes in glaucomatous eyes relative to their contralateral normal eyes, with OPs showing the earliest significant difference after only 3 weeks of high IOP. When different groups of unilateral glaucomatous rats were compared beyond 8 weeks of elevated IOP only the OPs showed a continued decrease with time and good discrimination between glaucoma and normal eyes. Over a 25 week period of high IOP the scotopic OPs measured with attenuated light stimuli declined at the rate of approximately 1.5% per week and provided the best ERG measure to monitor progression of retinal pathophysiology in the vein-occlusion rat glaucoma model.

Nitric oxide, microglial activities and neuronal cell death in the lateral geniculate nucleus of glaucomatous rats

The present study was initiated to investigate neuronal degeneration, microglial reactivity and possible roles of NO in the lateral geniculate nucleus (LGN) of glaucomatous rats. An experimental one-eye glaucoma model was created by cauterization of the limbal-derived veins. Neuronal cell viability was studied by immunostaining with antibody against neuronal nuclei. Changes of expressions of nitric oxide synthase I (NOS I), NOS II, ED 1, OX6 and OX42 in the LGN were studied by immunohistochemistry. NADPH-d histochemistry was also employed. In the experimental glaucomatous rats, the number of NeuN labelled neurons was significantly decreased in both the ipsi- and contra-lateral sides of the ventral LGN (vLGN) but not the dorsal LGN (dLGN) at 1 month post-operation and beyond. Expressions of NOS I and NADPH-d were notably increased from 1 week post-operation in the ipsilateral vLGN. In the contralateral side of the vLGN, however, this change was only observed from 1 month post-operation. No NOS II immunoreaction was observed in LGN of both the normal control and glaucomatous rats. Increased microglial reactivity as indicated by OX-42 immunoreactivity was first observed in both sides of the LGN at 1 week post-operation, and this was most significant especially at 1 and 2 months post-operation. The present results suggest that NO and microglial cells may play some important roles in the pathologic processes of neuronal degeneration in the LGN of glaucomatous rats.

Pattern of visually induced c-Fos expression in the LGN and visual cortex in acute glaucoma rats

Pattern of visually induced c-Fos expression in the LGN and visual cortex in acute glaucoma rats

Synthetic drug slows glaucoma in rats

Science NewsVolume 156, Issue 8 p. 119-119 This Week Synthetic drug slows glaucoma in rats Nathan Seppa, Nathan SeppaSearch for more papers by this author Nathan Seppa, Nathan SeppaSearch for more papers by this author First published: 01 July 2009 https://doi.org/10.2307/4011702AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume156, Issue821 August 1999Pages 119-119 RelatedInformation

ERG, EOG and OEP in retinal venous occulusion

Purpose. To functionally characterize the rat retina and optic nerve after chronic elevation of the intraocular pressure (IOP) using electroretinography (ERG) and computerized pupillometry.Methods. Chronic elevation of the IOP was induced in Brown Norway rats by combined injection of indocyanine green dye (ICG) into the anterior chamber and diode laser treatment, followed by ERG and pupil light reflex (PLR) monitoring.Results. Laser treatment induced significant elevation of the IOP in operated eyes for 6 weeks, with maximal values observed 14 days postoperatively (ctrl=18·4±2·4 and operated=35±8·4 mmHg; mean±sd). Preoperative values for the PLRratio were 68·5±4% (mean±sem; %). Three days postoperatively the PLRratio decreased to 60·3±10·3%, but was not significantly different compared to preoperative values (p>0·05, Kruskal-Wallis non-parametric test with Dunn's post-test). However, 7, 14 and 21 days postoperatively the PLR function dramatically decreased to 14·6+8·6, 11·5±6·7 and 12·6±4%, respectively, and was significantly smaller compared to preoperative values (p<0·01). At day 28 the PLR significantly recovered and was not significantly different compared to preoperative values (PLRratio=38·5±8·6, p>0·05). However, 35 days after surgery the PLR started to decrease once again in the operated eyes (PLRratio=17·2±7·4%) and was significantly smaller again compared to preoperative values (p<0·05). The PLR values continued to decrease until the end of experiment (60 days postoperatively). ERG analysis of operated eyes revealed significantly decreased amplitudes of a- and b-waves 10d postoperatively, while oscillatory potentials (OPs) and flicker ERG (flERG) amplitudes were not detectable. However, 28 days postoperatively OPs significantly, but temporarily recovered, while a-wave, b-wave and flERG amplitudes did not significantly change compared to values observed 10d postoperatively. The ERG analysis of the operated eyes revealed significantly reduced amplitudes 60 days postoperatively. Histological analysis revealed degeneration of all retina layers and optic nerve axons.Conclusions. Chronic ocular hypertension in rats produces dramatic damage to all retinal layers and optic nerves observed by morphological and functional methods which significantly correlate with the IOP elevation. Outer retina of glaucomatous rats seems to be more susceptible to the damage due to chronic elevation of the IOP. Chronic hypertensive rat eyes have capacity to temporarily recover function of the inner retina and optic nerve.