Study Of Retinal ~1H Magnetic Resonance Spectroscopy And Neuroprotection After Optic Nerve Injury

Purpose To investigate retinal metabolic changes in optic nerve transection (ONT) rats by 1H magnetic resonance spectroscopy(1H-MRS).Methods Fluorogold was injected into bilateral superior colliculi to retrogradely label retinal ganglion cells (RGCs) in adult Sprague-Dawley rats. Three days later, ONT was inflicted unilaterally. Another group of rats which did not undergo ONT were considered as controls. Rats were killed and retinas harvested from both eyes 2 weeks after ONT. RGCs densities were assessed from retinal whole mounts. Retinal metabolites were analyzed by 'H-MRS of retinal extracts. The expression of glutamate (Glu),γ-aminobutyric acid (GABA) and glial fibrillary acidic protein (GFAP) was examined using immunohistochemistry.Resu Its Compared with control, the retina in ONT rats had significantly decreased GABA, N-acetylaspartate (NAA), taurine (Tau), creatine (Cr) and increased alanine (Ala) concentrations. The Glu, glutamine (Gln) and Glx (Glu+Gln) concentrations were not significantly different. The mean density of RGCs reduced from 2249±87 cells/mm2 in control group to 320±56 cells/mm2 in ONT group. Glu and GABA immunoreactivity decreased and GFAP immunoreactivity increased remarkably.Conclusions RGCs death after ONT was associated with glutamatergic and GABAergic systems cycling deficit, as well as other metabolic disequilibrium.1H-MRS provided a method to monitor metabolic changes in the retina, and the alterations might draw important insight in the mechanisms and neuroprotection of RGCs loss follow axotomy. Objective To investigate the neuroprotective effects of hypericin on retinal ganglion cells (RGCs) in rat optic nerve crush model.Methods Twenty four Sprague-Dawly (SD) rats were divided into normal group, optic nerve crush group, hypericin-treated group and saline-treated group with 12 eyes in each. 2% fluorogold (FG) was injected into both sides of superior colliculus to label RGCs retrogradely. Seven days after labeling,5μL hypericin or saline was injected into the vitreous cavity after optic nerve crush. RGCs were counted 14 days later.Resu Its The densities of RGCs decreased sharply 14 days after injury. The survival rate of RGCs in optic nerve crush group, hypericin-treated group and saline-treated group was 50%,52% and 68%, respectively. The number of RGCs in saline-treated group and optic nerve crush group was lower than that in hypericin-treated group.Conclusions Intravitreal injection of hypericin can protect the retinal ganglion cell in rat optic nerve crush model. Hypericin may bring some further study domain in the development of neuroprotection drugs. Objective To observe the effect of lens injury on retinal ganglion cells survival and axons regeneration in optic nerve crushed rats.Methods Sprague-Dawly (SD) rats were divided into normal group, control group and treated group. Optic nerves of both eyes were crushed in control group. In treated group, 5μL saline was injected into both eyes and then it was divided into two groups, one with lens injury and one without lens injury. For normal group, the above treatment was not done. Seven days later, fluorogold (FG) was injected into both sides of superior colliculus of rats in each group. The number of retinal ganglion cells was determined in retinal wholemounts and frozen sections at day 14th. Growth associated protein-43(GAP-43), glial fibrillary acidic protein (GFAP) were detected by immunohistochemistry (IHC).Results The number of retinal ganglion cells in normal group, control group, treated group with lens injury and without lens injury were 1987±154,908±123,1206±134 and 800±112. The number of retinal ganglion cells in treated group with lens injury was greater than that in control group and treated group without lens injury (P<0.05). The expression of GAP-43 and GFAP by IHC also increased significantly.Conclusions Lens injury can increase the retinal ganglion cells survival in optic nerve crushed rats. It also can increase the expression of GAP-43 and GFAP in retina and the regeneration of axons. Objective To investigate the clinical curative effect and examination methods of optic neuritis patients by visual field, pattern visual evoked potential (P-VEP), fluorescence fundus angiography (FFA) and imaging.Methods One hundred patients with optic neuritis received examination of visual field, pattern visual evoked potential, fluorescence fundus angiography and imaging. Combined treatments including glucocorticoid, vitamine B, neurotrophic drugs, vasodilating agents and complex anisodine were given to the patients and the results of examination and therapy were observed.Results No obvious predisposition was discovered in a majority of patients. Corresponding nonspecific abnormal manifestations were observed in visual field, pattern visual evoked potential and fluorescence fundus angiography. Imagings, especially magnetic resonance imaging (MRI), have vital clinical value in finding insidious focus of infection. Eighty-five cases with visual acuity improved and 15 cases with visual acuity unchanged or decreased were observed after receiving combined treatments.Conclusions Promptly diagnosis based on various examination methods combined with comprehensive treatments play a key role in improving the prognosis and therapeutic effect of optic neuritis.