Brain lesions induced by monosodium glutamate [MSG] in adult and neonatal mice

ABSTRACT

The present study was carried out to assess the possible neurotoxicity of the flavour enhancer, monosodium glutamate [MSG] in adult and neonate mice through the administration of single dose of 5mg/g body weight in acute experiment and repeated doses of 2mg/g body weight in chronic experiment. Light and electron microscopic studies revealed that neonates were more susceptible to brain lesions than adults in acute experiment and their brains were more severely damaged in chronic experiment. The lesioned neurons were karyolysed whereas the glial cells showed variable degrees of damage As a neuroprotective response, astrocytes displayed proliferation. Cell death had led to the appearance of nerve fibre degeneration and brain lesions in many areas of the brain such as; most of the rostral areas of neocortex, hippocampus, pretectal nucleus, lateral geniculate nucleus, hypothalamus, superior colliculus and optic tracts. It is worth emphasising that the lesioned areas of the brain included visual and nonvisual centres. So it might be expected that vision could be affected. It may be that prolonged intake of glutamate caused a state of hyperdepolarization and that neither neuronal glutamate catabolism nor glial response were capable of removing excess glutamate. In conclusion it might be suggested that the use of MSG specially in baby food should be revised