Analysis of Tooth Enamel Structure and Mechanical Properties in Rats Induced Mono Sodium Glutamate (MSG)

@#Introduction: Formation of enamel begins in intrauterine. The process is prone to disturbances, for example bad nutrition intake. Monosodium Glutamate (MSG) is a food additive that is added to meals to improve the taste. Unmeasured use can result in physical abnormalities, growth, and immune system disruption. This research aim of this study was to analyze MSG consumption on rats during gestation and gestation to lactation on enamel structure and mechanical properties in their first offspring. Methods: Three groups of male rats, aged 21 days, which were born from mice induced by MSG during gestation (group 1), during gestation to lactation (group 2) and those without MSG (group 3 as a negative control group). Monosodium Glutamate is given daily at the dose of 1.54 mg/gr (body weight/ BW) orally, which starts on the fifth day of gestation until partition (23 days) in the first group and until weaning time (44 days) in the second group. Analysis of the structure and properties of enamel was performed on the lower left first molar using scanning electron microscope (SEM) and Vikers microhardness test. Results: The average enamel hardness in MSG induced mice during gestation, gestation and lactation periods, and without MSG was 242.7 Vickers hardness (HV); 238.3 HV and 309.1 HV respectively, while the porosity in the enamel structure is 13,1909%, 18,147% and 7,039%. Conclusion: MSG intake in mice during gestation and gestation to lactation results in abnormalities in the structure of the enamel and its mechanical properties in offspring.

Biochemical Changes in the Malnourished Rats Serum and Liver Exposed to Dietary Monosodium Glutamate

Monosodium glutamate (MSG) is a flavor enhancer. Its toxicity in a malnourished state appears not to have been fully investigated. This study was carried out to determine the effects of MSG on malnourished rats. Rats were randomly assigned into four groups of five rats/group. Group 1 rats were fed with malnourished feed; Group 2 rats received malnourished feed with dosed 1.6 mg/g MSG per body weight; Group 3 rats were fed with normal feed and dosed 1.6 mg/g MSG per body weight and Group 4 rats served as the control group (normal healthy rats) and were fed with normal feed for 28 days. After 28 days, the rats were sacrificed with the liver harvested and blood samples collected. Results from the study showed that malnourished rats had significantly lower levels of oxidative stress biomarkers including, anti-oxidants compared with the control. The levels of malondialldehyde concentration and xanthine oxidase activity were high in malnourished fed rats. Aspartate aminotransferase and alanine transaminase levels of malnourished and normal rats administered MSG were significantly low compared to the normal healthy suggesting that labialization occurs in liver leading to leakage of these enzymes from the liver to the serum. Malnourished rats showed significant decrease in body weight losing 48 grams after 28 days compared to malnourished and normal rats fed with MSG which recorded significant increase in body weight after 28 days adding 26 g and 42 g respectively.

Evaluation of the Changes in Some Liver Function and Haematological Parameters in MSG Fed Rats.

The effect of Monosodium glutamate (MSG) was evaluated on hepatic functions and haematological parameters in adult Wistar albino rats. The rats were randomly assigned into four (4) groups of five rats each. Group 1 served as the control while groups 2, 3 and 4 were fed diets supplemented with MSG at doses of 0.5, 1.0 and 5.0% per Kg of diet respectively. Following the 28 days of feeding, the rats were sacrificed and blood samples were collected for analyses. The haematological parameters except PCV were estimated using haematocytometer while the biochemical parameters were determined using Randox enzymatic kit. There was no significant difference (p>0.05) in PCV, WBC, RBC, total protein, albumin, direct and conjugated bilirubin in the rats fed with MSG at all levels of supplementation when compared with the control group. The Alkaline phosphatase (ALP) and Alanine aminotransferase (ALT) activities were increased with increase level of MSG and ranged from 35.00±0.17 - 59.00±1.23 U/L and 6.4-11.9 U/L respectively. There was no significant (p>0.05) difference in the levels of both serum ALP and ALT activities in the group fed 0.5% MSG when compared with the control group while there were significant (p>0.05) increase in the other treatment groups (1 and 5% MSG supplemented diets groups). The results therefore suggest that MSG at the levels of supplementation in the diets of the rats had no effect on the haematological indices but increased the liver function enzymes in the serum as the level of MSG increased in the diet.

Chronic Administration of Monosodium Glutamate under Chronic Variable Stress Impaired Hypothalamic-Pituitary-Adrenal Axis Function in Rats

The hypothalamic-pituitary-adrenal (HPA) axis is the primary endocrine system to respond to stress. The HPA axis may be affected by increased level of corticotrophin-releasing factors under chronic stress and by chronic administration of monosodium glutamate (MSG). The purpose of this study was to investigate whether chronic MSG administration aggravates chronic variable stress (CVS)-induced behavioral and hormonal changes. Twenty-four adult male Sprague-Dawley rats, weighing 200~220 g, were divided into 4 groups as follows: water administration (CON), MSG (3 g/kg) administration (MSG), CVS, and CVS with MSG (3 g/kg) administration (CVS+MSG). In addition, for the purpose of comparing the effect on plasma corticosterone levels between chronic stress and daily care or acute stress, 2 groups were added at the end of the experiment; the 2 new groups were as follows: naive mice (n=7) and mice exposed to restraint stress for 2 h just before decapitation (A-Str, n=7). In an open field test performed after the experiment, the CVS+MSG group significant decrease in activity. The increase in relative adrenal weights in the CVS and CVS+MSG group was significantly greater than those in the CON and/or MSG groups. In spite of the increase in the relative adrenal weight, there was a significant decrease in the plasma corticosterone levels in the CVS+MSG group as compared to all other groups, except the naive group. These results suggest that impaired HPA axis function as well as the decrease in the behavioral activity in adult rats can be induced by chronic MSG administration under CVS rather than CVS alone.