Evaluación semicuantitativa de los microelementos del esmalte en un modelo de obesidad inducido por glutamato monosódico en ratas / Semi-quantitative evaluation of enamel microelements in an obesity model induced by monosodium glutamate in rats

RESUMEN: En la actualidad, existen múltiples modelos experimentales de obesidad, unos de ellos es la utilización de glutamato monosódico (GMS), un potenciador del sabor ampliamente utilizado en industria alimentaria. Este GMS ha sido relacionado con obesidad, diabetes, insulino resistencia, así como en alteraciones en múltiples órganos, tales como testículos, riñón e hígado, entre otros. Ha sido reportado el efecto del GMS en estructuras orales, tales como las glándulas salivales, alterando su morfología y función. La relación del efecto del GMS frente a tejidos dentarios no ha sido reportada, siendo esto relevantes debido a la información que proporciona a disciplinas tales como arqueología científica, identificación forense, paleoecología y odontología. El objetivo del estudio fue observar la modificación de los elementos en la superficie dental, en un modelo de obesidad inducida por GMS, en ratas. Se utilizaron 12 ratas neonatas Sprague Dawley machos, divididas en dos grupos según exposición a GMS (Grupo Control y Grupo GMS 1: 4 mg/g peso de GMS, 5 dosis, mantenidas 16 semanas. Fue calculado el índice de masa corporal (IMC) e Índice de Lee, además de ser analizados el porcentaje de masa de los elementos C, O, Na, P, Ca, Fe y K en la superficie dental, mediante análisis semicuantitativo. Los resultados indican que GMS indujo obesidad en las ratas, así como alteraciones en los porcentajes de masa de los elementos en la superficie dental, evidenciándose disminución de Ca, P y O, además de aumentos en C y Fe. Según reportes previos, la obesidad inducida por GMS, causa alteraciones en secreción y composición salival, elemento íntimamente relacionado con la composición del esmalte, lo que vendría a explicar nuestros resultados. Entender la composición superficial del esmalte superficial podría ayudarnos a comprender de mejor manera la relación entre caries dentaria y obesidad.

SUMMARY: Monosodium glutamate (MSG) is a flavor enhancer widely used in the food industry. It has been associated with obesity, diabetes, insulin resistance, as well as alterations in multiple organs, such as testicles, kidney, liver, among others. While its effect on oral structures such as the salivary glands has been reported, the impact on dental tissues has not been described. Since this information is also relevant in fields such as forensic identification, palaeoecology and dentistry, the objective of the study was to observe alterations on the tooth surface in a model of obesity in rats induced by MSG. Twelve neonate male Sprague Dawley rats were used, divided into two groups according to MSG exposure (Control Group and MSG1 Group: 4 mg / g weight of MSG, 5 doses were maintained for 16 weeks. Body mass index (BMI) and Lee's index as well as mass percentage of elements C, O, Na, P, Ca, Fe and K on the tooth surface were evaluated by semi-quantitative analysis. In addition to increases in C and Fe, results indicate that MSG induced obesity and alterations in the percentages of mass on the tooth surface in rats, showing a decrease in Ca, P and O, According to previous reports, MSG induced obesity causes alterations in secretion and salivary composition, an aspect closely related to enamel composition, thus explaining our results. Enhanced knowledge of enamel surface composition may help improve our understanding of the relationship between dental caries and obesity.

Monosodium glutamate neonatal treatment induces cardiovascular autonomic function changes in rodents

OBJECTIVES: The aim of this study was to evaluate cardiovascular autonomic function in a rodent obesity model induced by monosodium glutamate injections during the first seven days of life. METHOD: The animals were assigned to control (control, n = 10) and monosodium glutamate (monosodium glutamate, n = 13) groups. Thirty-three weeks after birth, arterial and venous catheters were implanted for arterial pressure measurements, drug administration, and blood sampling. Baroreflex sensitivity was evaluated according to the tachycardic and bradycardic responses induced by sodium nitroprusside and phenylephrine infusion, respectively. Sympathetic and vagal effects were determined by administering methylatropine and propranolol. RESULTS: Body weight, Lee index, and epididymal white adipose tissue values were higher in the monosodium glutamate group in comparison to the control group. The monosodium glutamate-treated rats displayed insulin resistance, as shown by a reduced glucose/insulin index (-62.5%), an increased area under the curve of total insulin secretion during glucose overload (39.3%), and basal hyperinsulinemia. The mean arterial pressure values were higher in the monosodium glutamate rats, whereas heart rate variability (>7 times), bradycardic responses (>4 times), and vagal (~38%) and sympathetic effects (~36%) were reduced as compared to the control group. CONCLUSION: Our results suggest that obesity induced by neonatal monosodium glutamate treatment impairs cardiac autonomic function and most likely contributes to increased arterial pressure and insulin resistance.

Mechanism of food additive [monosodium glutamate]- induced obesity a molecular study

There is no question that there is an obesity epidemic in our country, as well as in some other countries. Obesity during pregnancy increases maternal and fetal morbidity and is a risk factor for gestational diabetes and hypertensive disorders of pregnancy. There are many causes of obesity from them the bad use of food additives, the monosodium glutamate is considered one of the most popular food additives. The results of previous studies on the role of monosodium glutamate in developing of obesity are controversial so the aim of this paper is to determine the role of MSG in developing obesity through studying its effect on Ob gene expression and leptin receptor-b gene expression and to determine its effect on some cardiac disease indicators as apo-A[1] and apo-B. We used in this study 60 pregnant female rats which were divided into 2 groups, control group and group supplemented with monosodium glutamate. In all rats, determination of biochemical parameters as serum glucose, insulin, leptin, total lipids, cholesterol HDL, LDL, VLDL, apo A1, apo B, as well as determination of Ob and leptin receptor-b gene expression were done. Our results indicated that the administration of monosodium glutamate is accompanied with increase of Ob gene expression, leptin, insulin, lipoprotein B, lipogram, glucose and decrease of brain leptin receptor-b gene expression, lipoprotein lipase activity and HDL concentrations. It can be concluded that the administration of MSG may be considered as one of the main causes of obesity by increasing of leptin and insulin resistance and so developing of hyperphagia. Also it is accompanied by increasing the risk of atherosclerosis through development of diabetes mellitus type II and increasing total cholesterol and LDL. Moreover, maternal obesity is a serious condition that significantly impacts health of mothers and their children

Evaluation of body growth and myoenteric neurons of Wistar rats after neonatal treatment with monosodium glutamate

This work aimed at evaluating how the neonatal treatment with monosodium glutamate reflects on body parameters and on myoenteric neurons of Wistar rats. Male rats were injected with monosodium glutamate during the first five postnatal days. Body growth was recorded until the age of 90 days, when the animals were killed. Fasting plasma glucose, caloric density and weight of organs were assayed. Gastric and duodenal whole-mounts stained with NADH diaphorase were observed for neuronal numbers and sizes. Growth, relative weight of organs and testicular caloric density of the injected rats were smaller than those of the controls, while their Lee index and relative fat content were greater. The number of duodenal neurons and the mean size of gastric neurons were smaller in the injected animals. These results are discussed in light of the endocrine, autonomic and behavioral changes stemming from the lesion of the hypothalamic arcuate nucleus by monosodium glutamate.

Avaliação do crescimento corporal e dos neurônios mioentéricos de ratos Wistar após tratamento neonatal com glutamato monossódico. Este trabalho objetivou avaliar como o tratamento neonatal com glutamato monossódico se reflete em parâmetros corporais e nos neurônios mioentéricos de ratos Wistar. Ratos machos foram injetados com glutamato monossódico durante os primeiros 5 dias após o nascimento. O crescimento corporal foi registrado até os 90 dias, quando os animais foram sacrificados. Glicose plasmática de jejum, densidade calórica e peso dos órgãos foram avaliados. Preparados de membrana gástricos e duodenais corados com NADH-diaforase foram observados quanto a número e tamanho dos neurônios. Crescimento, peso relativo dos órgãos e densidade calórica testicular dos ratos injetados foram menores que nos controles, enquanto o índice de Lee e o conteúdo relativo de gordura foram maiores. O número de neurônios duodenais e o tamanho médio dos neurônios gástricos foram menores nos animais injetados. Esses resultados são discutidos a luz das alterações endócrinas, autonômicas e comportamentais resultantes da lesão do núcleo arqueado hipotalâmico pelo glutamato monossódico.

impact of barley on monosodium glutamate induced changes in duodenal villi of young mice light and electron microscopic study

Diet is an important factor in the regulation of body physiological activities especially at young ages and its maintenance in later life. Barely as high fibre diet, affects the functions of the gastrointestinal tract. In the present work, 40 young mice were used to investigate the effect of barley on the intestinal changes that might occur after monosodium glutamate [MSG] induced obesity-despite the absence of overeating. Animals were divided into 4 groups each of 10 mice, the first group served as control, fed on ordinary balanced diet and received 0.5 ml of distilled water for 21 days. The second group was fed on ground barley ad libitum for 21 days. The third group received MSG in daily oral dose of 2 mg/g body weight for 21 days. The fourth group was fed on ground barley ad libitum simultaneously with the same daily dose of MSG as in group three for the same period. Light and electron microscopic investigation of the group of animals that received MSG revealed localized loss of microvillus border and vacuolation of some enterocytes while other cells showed apparent hyperplasia. The core of the villi exhibited edema and cellular infilteration. In addition, the mitochondria revealed marked loss of cristae. Scanning electron microscopic examination [SEM] showed deformed villi in some areas while other villi exhibited sloughing of their tips. On the contrary, in animals treated with MSG simultaneously with barley, the villi revealed structure almost similar to that of the villi of control group. Consequently, based on these results, it is possible to suggest that dietary barley may have a significant importance in protection against MSG-induced perturbation in duodenal villi

Efeito da vagotomia troncular em ratos injetados na fase neonatal com glutamato monossódico: estudo biométrico / Effect of truncal vagotomy in rats neonatally injected with monosodium glutamate: biometry study

Obesidade hipotalâmica pode ocorrer em humanos e pode ser reproduzida, experimentalmente, por lesão do VMH em ratos. Esta obesidade pode ser revertida por vagotomia troncular (VT), devido à redução da ingestão alimentar e da insulinemia mediada pelo nervo vago. Experimentalmente, a injeção de MSG causa lesão em nível de ARC. O objetivo deste trabalho é avaliar os efeitos do MSG em ratos e se VT os altera. Estudou-se 52 ratos Wistar machos, divididos em dois grupos de 26 animais, um submetido à injeção de MSG na fase neonatal e outro à de solução salina. Aos 30 dias de vida, após nova divisão, obteve-se: grupo MSG, submetido à VT (VTMSG), e outro à laparotomia (LAPMSG); grupo SALINA, submetido à VT (VTSAL), e outro à laparotomia (LAPSAL). Obteve-se peso, CNA e índice de Lee. O consumo alimentar foi obtido dos 30 aos 90 dias de vida. Aos 90 dias, após eutanásia, mensurou-se peso, CNA, índice de Lee e gordura perigonadal. Análise estatística foi realizada pelo "t de Student". Constatou-se que o MSG provoca redução do CNA e aumento do índice de Lee aos 30 dias de vida, e provoca redução do peso e do CNA, aumento do índice de Lee e da gordura perigonadal aos 90 dias e aumento do consumo alimentar dos 30 aos 90 dias de vida. A VT provoca redução do peso, do índice de Lee e da gordura perigonadal, e tendência à redução do CNA no rato injetado com MSG. A VT provoca redução de consumo alimentar nos primeiros 30 dias de pós-operatório, mas com tendência a maior consumo nos 30 dias subseqüentes. Conclui-se que o MSG injetado na fase neonatal provoca aumento do consumo alimentar e da adiposidade e causa redução da estatura e do peso do animal dos 30 aos 90 dias de vida. E que a VT, realizada aos 30 dias de vida, provoca redução do consumo alimentar nos primeiros 30 dias de pós-operatório, da adiposidade e do peso.

Reacciones adversas a alimentos y sus aditivos / Adverse reactions to food and their additives

Las reacciones adversas a alimentos es un tema de importancia en la práctica médica y su trascendencia en pediatría adquiere mayor relieve día a día. El estilo de vida y los cambios de hábitos alimentarios que ha impuesto la vida moderna conducen al consumo de una cantidad de elementos ajenos al nutriente natural cuyas consecuencias recién se comienzan a identificar. La mayor parte de esta problemática está rodeada de profundas controversias basadas en la falta de estudios adecuados en muchos casos, pero en muchos otros, en una falta de preocupación por el tema