Neurotoxicity Of Exogenous Monosodium Glutamate To Neurons Of Internal Tunic Of Eyeball

To study the toxic effect of exogenous monosodium glutamate on neurons of internal tunic of eyeball, two groups of guinea pigs were given monosodium glutamate at 3g/kg/day in peritoneum for 3 days (Group MG-3D) and 7days (Group MG-7D) respectively and the normal saline group (Group SL-5D) were given equivalent saline and then all of 3 groups were fed for 10 days. Afterwards, the animals were killed with pentobarbital sodium and their eyes were made into sections. The thickness of retinal layers, density of neurons and cell morphological changes were measured. Results are as follow. Group MG-3D showed a decrease in density of ganglion cell layer, and some cells appeared pycnotic. Group MG-7D had severe damage of ganglion cells. In addition, cell pycnosis and death of neurons were observed in the ganglion cell layer. The density of ganglion cells and bipolar cells were both reduced. The thickness of the inner nuclear layer and inner plexiform layer, ganglion layer and nerve fiber layer became thinner, so did total thickness of retina. Therefore, the inner tunic of eyeball of juvenile guinea pig is susceptible to monosodium glutamate toxicity; the ganglion cells are especially vulnerable, followed by bipolar cells.