Therapeutic role of adipose tissue-derived stem cells versus microvesicles in a rat model of cerebellar injury

Determining the effects of in ovo administration of monosodium glutamate on the embryonic development of brain in chickens

Monosodium glutamate (MSG) is a popular flavor enhancer largely used in the food industry. Although numerous studies have reported the neurotoxic effects of MSG on humans and animals, there is limited information about how it affects embryonic brain development. Thus, this study aimed to determine the effects of in ovo administered MSG on embryonic brain development in chickens. For this purpose, 410 fertilized chicken eggs were divided into 5 groups as control, distilled water, 0.12, 0.6 and 1.2 mg/g egg MSG, and injections were performed via the egg yolk. On days 15, 18, and 21 of the incubation period, brain tissue samples were taken from all embryos and chicks. The mortality rates of MSG-treated groups were significantly higher than those of the control and distilled water groups. The MSG-treated groups showed embryonic growth retardation and various structural abnormalities such as abdominal hernia, unilateral anophthalmia, hemorrhage, brain malformation, and the curling of legs and fingers. The relative embryo and body weights of the MSG-treated groups were significantly lower than those of the control group on incubation days 18 and 21. Histopathological evaluations revealed that MSG caused histopathological changes such as necrosis, neuronophagia, and gliosis in brain on incubation days 15, 18, and 21. There was a significant increase in the number of necrotic neurons in the MSG-treated groups compared to the control and distilled water groups in the hyperpallium, optic tectum and hippocampus regions. Proliferating cell nuclear antigen (PCNA) positive cells in brain were found in the hyperpallium, optic tectum, and hippocampus regions; there were more PCNA(+) immunoreactive cells in MSG-treated groups than in control and distilled water groups. In conclusion, it was determined that in ovo MSG administered could adversely affect embryonic growth and development in addition to causing necrosis in the neurons in the developing brain.