Investigation of the Effects of Monosodium Glutamate on the Embryonic Development of the Eye in Chickens

MSG is the most ubiquitous food additive in the food industry. The aim of this report was to investigate the effects of in ovo MSG administration on embryonic chicken eye development using histological and histometric methods. A total of 410 fertilized eggs obtained from Babcock Brown laying hens (Gallus gallus domesticus) were used and divided into 5 groups: I (untreated control), II (vehicle control), III (0.12 mg/g egg MSG), IV (0.6 mg/g egg MSG), and V (1.2 mg/g egg MSG), and injections were performed via the egg yolk. At incubation day 15, 18, and 21, 6 embryos from each group were sacrificed by decapitation and pieces of eye tissue were obtained. In all MSG groups, it was determined that both corneal epithelium thickness and total corneal thickness decreased at incubation time points 15, 18, and 21 days compared with the controls (p < 0.05). The total retinal thickness, thickness of the outer nuclear layer (ONL), inner nuclear layer (INL), ganglion cell layer (GL), and nerve fibre layers (NFL), as well as the number of ganglion cells decreased significantly at incubation days 15, 18, and 21 (p < 0.05), and degenerative changes such as vacuolar degeneration and retinal pigment epithelial detachment were also observed. In conclusion, MSG in ovo administration can affect the cornea and distinct layers of retinal cells.

Subcutaneous administration of monosodium glutamate to pregnant mice reduces weight gain in pups during lactation

Administering monosodium glutamate (MSG) to neonatal rodents induces obesity and type 2 diabetes. In addition, several studies have shown that MSG administered to pregnant animals can cross the placenta and reach the foetus. The present study was performed to investigate the effects of administering MSG to pregnant ICR mice on dam and neonatal growth. Pregnant mice were treated with 60 or 120 mg MSG once daily from day 5 of pregnancy to one day before parturition by subcutaneous injection. In addition, the body weights of the neonates were determined until nine weeks of age. The birth weights of neonates were not different between the control and MSG-treated groups. However, MSG treatment resulted in a lower body weight gain of neonates during lactation. In addition, this underweight of the MSG-treated group at weaning returned to normal compared with the control group at five weeks of age. Cross-fostering experiments indicated that the lower body weight gain of neonates in the MSG-treated group during lactation was due to its effects on the dam. Serum prolactin levels and mammary gland development of the mice were examined next to determine the reasons for this lactation problem. Although there were no differences in prolactin levels, morphological analyses of the mammary glands revealed apparent differences, including low numbers and altered phenotype of alveoli, between the control and MSG-treated groups. Taken together, our results show that treating pregnant mice with excess MSG induced lower neonate body weight gain during lactation.

Molecular dynamics simulation of the cooperative effect by different force fields in monosodium glutamate aqueous solution

Different force fields (GROMOS and OPLS) in conjunction with different water (SPC, SPCE, TIP3P, TIP4P and TIP5P) were assessed using molecular dynamics simulations of monosodium glutamate (MSG) aqueous solution.

Synergistic Interactions between Commonly Used Food Additives in a Developmental Neurotoxicity Test

Exposure to non-nutritional food additives during the critical development window has been implicated in the induction and severity of behavioral disorders such as attention deficit hyperactivity disorder (ADHD). Although the use of single food additives at their regulated concentrations is believed to be relatively safe in terms of neuronal development, their combined effects remain unclear. We therefore examined the neurotoxic effects of four common food additives in combinations of two (Brilliant Blue and L-glutamic acid, Quinoline Yellow and aspartame) to assess potential interactions. Mouse NB2a neuroblastoma cells were induced to differentiate and grow neurites in the presence of additives. After 24 h, cells were fixed and stained and neurite length measured by light microscopy with computerized image analysis. Neurotoxicity was measured as an inhibition of neurite outgrowth. Two independent models were used to analyze combination effects: effect additivity and dose additivity. Significant synergy was observed between combinations of Brilliant Blue with L-glutamic acid, and Quinoline Yellow with aspartame, in both models. Involvement of N-methyl-D-aspartate (NMDA) receptors in food additive-induced neurite inhibition was assessed with a NMDA antagonist, CNS-1102. L-glutamic acid- and aspartame-induced neurotoxicity was reduced in the presence of CNS-1102; however, the antagonist did not prevent food color-induced neurotoxicity. Theoretical exposure to additives was calculated based on analysis of content in foodstuff, and estimated percentage absorption from the gut. Inhibition of neurite outgrowth was found at concentrations of additives theoretically achievable in plasma by ingestion of a typical snack and drink. In addition, Trypan Blue dye exclusion was used to evaluate the cellular toxicity of food additives on cell viability of NB2a cells; both combinations had a straightforward additive effect on cytotoxicity. These data have implications for the cellular effects of common chemical entities ingested individually and in combination.