Neuroprotection of the rat’s retinal ganglion cells against glutamate-induced toxicity

Abstract

Purpose Glutamate is one of the contributors to retinal ganglion cells degeneration. The potential neuroprotective function of taurine, which is an endogenous amino acid molecule in the retina, was investigated. Materials and methods A prospective comparative nonrandomized controlled study was conducted from November 2012 to January 2015. A total of 24 adult male albino rats were divided into four groups. Balanced salt solution (BSS) (0.1 ml) was injected intravitreally in the control group, and 0.1 ml of glutamate (40 nmol) was injected once intravitreally in the glutamate group. Taurine of 25 mg/kg was injected once intraperitoneally in the taurine group. In the fourth group, 0.1 ml of glutamate was injected intravitreally, and at the same time, each rat received taurine intraperitoneally. Three days after the injection, animals were killed, and eyes were enucleated and processed for histopathological and immunohistochemical staining for glial fibrillary acidic protein, synaptophysin, vascular endothelial growth factor, and caspase-3. Results Extensive damage and disruption of the structure of the retina with significant decrease in the mean total, outer, and inner retinal thickness and ganglion cell counts was found following glutamate intravitreal injection, with significant improvement of this picture in the taurine and the combined groups (P Conclusion Taurine protects the retina against glutamate excitotoxicity and could have clinical implications in protecting the ganglion cells from several ophthalmic diseases such as glaucoma and diabetic retinopathy.