Monosodium glutamate (MSG):promoter of neurotoxicity, testicular impairment, inflammation and apoptosis in male rats

Abstract

Monosodium glutamate (MSG) is one of the most common food additives extensively used as a flavor enhancer. MSG induced lipid peroxidation and inflammation. The present study aimed to assess the neurotoxicity, testicular impairment, inflammation and apoptosis induced by MSG. Thirty adult male Wistar rats, weighing about 180-200 g were assigned equally into five groups, each consists of six rats. Animals of Group I are controls and they received distilled water, whereas animals of Groups II, III, IV and V were given oral daily doses of MSG 0.8, 1, 2 and 3 g/kg body weight, respectively for consecutive 70 days. Administration of different doses of MSG revealed a significant elevation in the levels of malondialdehyde (MDA), nitric oxide (NO), β amyloid 1-42, proinflammatory cytokines (IL-6, TNF-α), cholesterol and sperm abnormality while it showed reduction in the level of GSH and SOD, CAT and GST antioxidant enzymes activities, sperm count and sperm motility. MSG led to disruption in neurotransmitter levels; serotonin, norepinephrine, glutamate and GABA, also disorders in sexual hormones; testosterone, FSH and LH. The present results were confirmed by histological and immunohistochemical observations that obviously designate the neurodegeneration and reproductive toxicity. In conclusion, administration of low and high doses of MSG provoke deleterious effects on oxidant/ antioxidant markers, neurotransmitters, inflammatory cytokines, sexual hormones, brain and testes structures. Prominence hazards of lasting exposure to low and high doses of MSG on neuronal and testicular health. Therefore, its use should be restricted.