Liver proteome of mice with different genetic susceptibilities to the effects of fluoride

ABSTRACT A/J and 129P3/J mice strains have been widely studied over the last few years because they respond quite differently to fluoride (F) exposure. 129P3/J mice are remarkably resistant to the development of dental fluorosis, despite excreting less F in urine and having higher circulating F levels. These two strains also present different characteristics regardless of F exposure. Objective In this study, we investigated the differential pattern of protein expression in the liver of these mice to provide insights on why they have different responses to F. Material and Methods Weanling male A/J and 129P3/J mice (n=10 from each strain) were pared and housed in metabolic cages with ad libitum access to low-F food and deionized water for 42 days. Liver proteome profiles were examined using nLC-MS/MS. Protein function was classified by GO biological process (Cluego v2.0.7 + Clupedia v1.0.8) and protein-protein interaction network was constructed (PSICQUIC, Cytoscape). Results Most proteins with fold change were increased in A/J mice. The functional category with the highest percentage of altered genes was oxidation-reduction process (20%). Subnetwork analysis revealed that proteins with fold change interacted with Disks large homolog 4 and Calcium-activated potassium channel subunit alpha-1. A/J mice had an increase in proteins related to energy flux and oxidative stress. Conclusion This could be a possible explanation for the high susceptibility of these mice to the effects of F, since the exposure also induces oxidative stress.

Efeito da ingestão crônica do fluoreto sobre o sistema oxidante/antioxidante de ratos / Effect of chronic fluoride intake in the oxidant/antioxidant system of rats

A ingestão excessiva de fluoreto por um longo período de tempo pode resultar em fluorose, que pode causar manifestações dentárias e esqueléticas. Danos metabólicos, funcionais e estruturais causados pela fluorose crônica tem sido relatados em vários tecidos. O objetivo deste estudo foi avaliar os efeitos do fluoreto administrado na água de beber, da administração de fluoreto na água de beber na defesa antioxidante de ratos. Quatro grupos de ratos wistar foram usados (n=10/grupo). Os animais receberam água de beber contendo 0 (controle), 5, 15 ou 50 ppm de fluoreto durante 60 dias. Eles foram eutanasiados e os tecidos (fígado, rins e coração) e plasma foram coletados e homogenizados. Superóxido dismutase (SOD), catalase (CAT), glutationa peroxidase (GPx), glutationa reduzida (GSH), substâncias antioxidantes totais (SAT), substâncias reativas ao ácido tiobarbitúrico (TBARS), hidroperóxido de lipídios (HL) e fluoreto foram análisadas. Dados foram analisados por ANOVA e teste de Tukey ou Kruskal-Wallis e teste de Dunn (p<0,05). Nos rins, SOD, GPx, GSH e SAT diminuiram e fluoreto e HL aumentaram significantivamente. No fígado, CAT e TBARS diminuiram, SOD, HL e SAT aumentaram significativamente. No coração, GPx aumentou significativamente. No plasma, SOD e HL diminuiram significativamente. Em resumo, esses resultados mostram que a administração crônica de fluoreto altera o sistema antioxidante de ratos. Nosso dados sugerem que a exposição em níveis elevados de fluoreto, a conversão do ânion superóxido em água nos rins parecem ocorrer principalmente através da SOD e CAT, com baixa participação do sistema glutationa, diferindo do que parece ocorrer no fígado.

Excessive fluoride intake over a long period of time could result in fluorosis, which can lead to dental and skeletal manifestations. Metabolic, functional and structural damages caused by chronic fluorosis have been reported in many tissues. The aim of this study was to evaluate the effect of fluoride, administered in drinking water, in the antioxidant defense of rats. Four groups of Wistar rats were included (n=10/group). The animals received drinking water containing 0 (control), 5, 15 or 50 ppm of fluoride during 60 days. They were euthanized and the tissues (liver, kidney and heart) and plasma were collected and homogenized. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), antioxidants, thiobarbituric acid reactive substances (TBARS), lipid hydroperoxide (LH), and fluoride were analyzed. Data were analyzed by ANOVA and Tukeys test or Kruskal-Wallis and Dunns tests (p<0.05). In the kidney SOD, GPx, GSH and SAT decreased and fluoride and LH increased significantly. In the liver, CAT and TBARS decreased and fluoride, SOD, LH and SAT increased significantly. In the heart, GPx increased significantly. In the plasma, SOD and LH decreased significantly. In summary, these results show that chronic fluoride administration alters the antioxidant system of the rats. Our data suggest that upon exposure to high levels of fluoride, the conversion of the superoxide anion to water in the kidney seems to occur mainly through the SOD and CAT, with a low participation of the glutathione system, differing from what seems to occur in the liver.

Efeito da ingestão crônica do fluoreto sobre o sistema oxidante/antioxidante de ratos / Effect of chronic fluoride intake in the oxidant/antioxidant system of rats

A ingestão excessiva de fluoreto por um longo período de tempo pode resultar em fluorose, que pode causar manifestações dentárias e esqueléticas. Danos metabólicos, funcionais e estruturais causados pela fluorose crônica tem sido relatados em vários tecidos. O objetivo deste estudo foi avaliar os efeitos do fluoreto administrado na água de beber, da administração de fluoreto na água de beber na defesa antioxidante de ratos. Quatro grupos de ratos wistar foram usados (n=10/grupo). Os animais receberam água de beber contendo 0 (controle), 5, 15 ou 50 ppm de fluoreto durante 60 dias. Eles foram eutanasiados e os tecidos (fígado, rins e coração) e plasma foram coletados e homogenizados. Superóxido dismutase (SOD), catalase (CAT), glutationa peroxidase (GPx), glutationa reduzida (GSH), substâncias antioxidantes totais (SAT), substâncias reativas ao ácido tiobarbitúrico (TBARS), hidroperóxido de lipídios (HL) e fluoreto foram análisadas. Dados foram analisados por ANOVA e teste de Tukey ou Kruskal-Wallis e teste de Dunn (p<0,05). Nos rins, SOD, GPx, GSH e SAT diminuiram e fluoreto e HL aumentaram significantivamente. No fígado, CAT e TBARS diminuiram, SOD, HL e SAT aumentaram significativamente. No coração, GPx aumentou significativamente. No plasma, SOD e HL diminuiram significativamente. Em resumo, esses resultados mostram que a administração crônica de fluoreto altera o sistema antioxidante de ratos. Nosso dados sugerem que a exposição em níveis elevados de fluoreto, a conversão do ânion superóxido em água nos rins parecem ocorrer principalmente através da SOD e CAT, com baixa participação do sistema glutationa, diferindo do que parece ocorrer no fígado.

Excessive fluoride intake over a long period of time could result in fluorosis, which can lead to dental and skeletal manifestations. Metabolic, functional and structural damages caused by chronic fluorosis have been reported in many tissues. The aim of this study was to evaluate the effect of fluoride, administered in drinking water, in the antioxidant defense of rats. Four groups of Wistar rats were included (n=10/group). The animals received drinking water containing 0 (control), 5, 15 or 50 ppm of fluoride during 60 days. They were euthanized and the tissues (liver, kidney and heart) and plasma were collected and homogenized. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), antioxidants, thiobarbituric acid reactive substances (TBARS), lipid hydroperoxide (LH), and fluoride were analyzed. Data were analyzed by ANOVA and Tukeys test or Kruskal-Wallis and Dunns tests (p<0.05). In the kidney SOD, GPx, GSH and SAT decreased and fluoride and LH increased significantly. In the liver, CAT and TBARS decreased and fluoride, SOD, LH and SAT increased significantly. In the heart, GPx increased significantly. In the plasma, SOD and LH decreased significantly. In summary, these results show that chronic fluoride administration alters the antioxidant system of the rats. Our data suggest that upon exposure to high levels of fluoride, the conversion of the superoxide anion to water in the kidney seems to occur mainly through the SOD and CAT, with a low participation of the glutathione system, differing from what seems to occur in the liver.

Resistência aos ácidos conferida à dentina pelos cimentos de ionômero de vidro: [revisão] / Dentin resistence to acids promoted by the glass ionomer cements: [review]

Introdução: as principais características dos CIVs são: liberação de flúor, biocompatibilidade, adesividade aos tecidos dentais duros e expansão térmica linear próxima à dentina. Objetivo: avaliar a capacidade dos cimentos de ionômero de vidro de promover à dentina maior resistência frente aos ácidos e microrganismos presentes na cavidade oral, discutindo a suposta bioatividade desse material relacionada ao substrato dentinário em diversas situações. Revisão de literatura: são inúmeras as opções e possibilidades de indicação dos CIVs, porém, a situação clínica deve ser avaliada com critério para escolher o material mais viável e aquele que ofereça o maior número de vantagens. Conclusões: os CIVs apresentam adesividade a estrutura dental, proporcionam vedamento marginal, reduzem a micro infiltração e/ou a passagem de nutrientes para os microorganismos que porventura possam estar presentes na cavidade. Devido à liberação de fluoretos, os CIVs apresentam potencial remineralizador ou paralisador mesmo em dentina cariada.

Introduction: the main characteristics of GICs are: fluoride release, biocompatibility, adhesion to dental hard tissues and linear thermal expansion similar the dentin. Aim: this literature review, based on the work currently available, evaluated the ability of glass ionomer cements to promote greater dentin resistance against acids and microorganisms presents in the oral cavity, discussing the supposed bioactivity of this material related to dentinary substrate in various situations. Literature review: there are countless options and possibilities for indication of GICs, however, the clinical situation must be evaluated on the criteria for selecting the material most viable and one that offers the greatest number of advantages. Conclusion: it was concluded that the GICs exhibit adhesion to tooth structure, providing marginal sealing, reduce microleakage and / or the passage of nutrients to the microorganisms who may be present in the cavity. Due to the release of fluoride, GICs have potential remineralizing paralyzing or even in carious dentin.

Dental fluorosis and its association with the use of fluoridated toothpaste among middle school students of Delhi.

Introduction: Fluorosis can manifest as dental fluorosis (seen mostly in secondary dentition), skeletal fluorosis, and systemic fluorosis. Groundwater with high fluoride concentrations, diet rich in fish and tea, indoor air-pollution, and use of fluoride toothpastes may contribute considerably to total exposure. Objective: To assess the prevalence of dental fluorosis and associated factors particularly fluoridated toothpastes, among middle school children of a resettlement colony in Delhi. Materials and Methods: This survey was conducted among the middle school students (VI th -VIII th ) studying in three government schools of Sangam Vihar, South Delhi. Students were examined for dental fluorosis by experts. A pre-structured questionnaire was used to obtain data regarding age, source of drinking water, toothpaste used, etc. Height, weight, and hemoglobin were recorded. Two repeat visits were made. Out of 432 students enrolled in these schools, 413 students were examined. Statistics: Descriptive and chi-square statistics were used. Results: Dental fluorosis was prevalent in 121 (29.3%) study subjects. It was significantly more in children of age 13 years or above, in those who used fluoridated toothpaste for dental cleaning (P=0.033) and in anemic children (P<0.001). However, there was no significant association of disease with gender (P=0.02), source of drinking water (P=0.417), and with BMI (P=0.826). Conclusion: As dental fluorosis is very common (in about one-fourth) among the middle school children, in this resettlement colony of Delhi, various control measures e.g. discouraging the fluoridated toothpastes, educating parents about fluorosis, de-fluoridation of water in the high risk areas, etc may help to tackle this situation.

Fingernail may not be a reliable biomarker of fluoride body burden from dentifrice

Fingernail has been suggested as a biomarker of fluoride (F) body burden, but there is no consensus if it would be a reliable indicator of F exposure from dentifrice. Therefore, the present study was conducted to investigate if fingernails would have sensitivity to detect F exposure from dentifrice in young children. Twenty-three 1-3-year-old children living in the city of Piracicaba (0.72 ppm F in water), Brazil, were enrolled in two phases of different F exposure: in phase A (1st to 11th week), they were exposed to the combination of F from diet (solids and liquids) and dentifrice (1,500 µg F/g as MFP), and in phase B (12th to 29th week), only to F from diet (the use of F dentifrice was interrupted). Fingernails were weekly clipped during 35 weeks for F determination. F intake from diet and dentifrice in each phase was also determined. Both analyses were made with ion-specific electrode. F intake (Mean ± SD) was significantly higher (p<0.01) when the children were exposed to F from diet+dentifrice than only to F from diet (0.086 ± 0.032 and 0.040 ± 0.009 mg F/day/kg body weight, respectively). However, F concentrations in nails collected during the whole experimental period of 35 weeks presented great variation with no trend of decreasing after F dentifrice intake interruption. The findings suggest that fingernail may not be a reliable F biomarker of body burden from dentifrice.

As unhas têm sido consideradas um biomarcador para a exposição ao flúor (F), mas não há consenso se é um indicador confiável para exposição ao F a partir do dentifrício. Vinte e três crianças, com idade entre 1 a 3 anos, moradoras de Piracicaba (0,72 ppm F na água), Brasil, foram submetidas a duas fases de diferentes exposição ao F: fase A (1a a 11a semanas), as crianças foram expostas à combinação de F a partir da dieta (sólidos e líquidos) e dentifrício (1500 µg F/g como MFP); e na fase B (12ª a 29ª semanas), apenas ao F da dieta, uma vez que usaram dentifrício não fluoretado. As unhas das mãos foram coletadas semanalmente durante 35 semanas para determinação de F. A exposição ao F a partir da dieta e dentifrício foi também determinada. Ambas análises foram feitas com eletrodo específico para F. A exposição ao F foi significativamente maior (p<0,001) quando as crianças foram expostas ao F da dieta + dentifrício que ao F da dieta (0,086 ± 0,032 e 0,040 ± 0,009 mg F/kg corpóreo/dia, respectivamente). Entretanto, a concentração de F nas unhas coletadas durante todo o período experimental não diminuiu após a interrupção da ingestão do F a partir do dentifrício. Os resultados sugerem que as unhas das mãos não são um biomarcador confiável para refletir a exposição ao F pelo dentifrício.

Prevalencia de fluorosis dental en áreas fluoruradas y no fluoruradas de la ciudad de Mérida, Venezuela / Prevalence of dental fluorosis in fluoridated and non-fluoridated areas of the Merida city, Venezuela

El propósito de este estudio fue determinar la prevalencia e intensidad de fluorosis dental en escolares de 10 a 13 años de edad residentes en áreas fluoruradas y áreas no fluoruradas de la ciudad de Mérida, Venezuela. El índice de Dean fue utilizado para estimar la severidad de fluorosis dental en una muestra de 834, los cuales fueron examinados en 8 escuelas seleccionadas aleatoriamente. Se confirmó el lugar de residencia mediante un cuestionario de fluoruro que recogió información acerca de los factores de riesgo secundarios: lugar de residencia anterior, tipo de agua de consumo, prescripción de tabletas, gotas o enjuagues con fluoruro, hábitos de cepillado, uso de dentífricos y su ingestión en el momento del cepillado. La prevealencia de fluorosis fue del 36 por ciento. La asociación entre fluorosis y lugar de residencia fue significativa, pues la razón de proporcionalidad fue de 2.39. La categoría de fluorosis mayormente encontrada fue la forma "muy leve"