Alterações no esmalte dentário de ratos a partir da exposição perinatal ao Bisfenol A
Carregando...
Data
2020-11-06
Autores
Costa, Silas Alves [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
A amelogênese é um processo sensível às interferências de fatores genéticos, traumáticos, hormonais, de agentes medicamentosos e a alguns poluentes. O Bisfenol A (BPA) é um desregulador endócrino que tem sido sugerido como fator de interferência em processos importantes do período perinatal. OBJETIVO: Avaliar o desenvolvimento e a microestrutura do esmalte dentário de ratos a partir da exposição ao BPA durante o período gestacional e de amamentação. METODOLOGIA: Após o acasalamento e confirmação da prenhez, seis ratas (Rattus norvegicus, albinus, Holtzman) foram aleatoriamente distribuídas em três grupos que receberam diariamente, no Grupo 1: dose intragástrica de BPA (5 μg/kg) durante toda a gestação e até o período de desmame dos filhotes (21 dias após o nascimento); Grupo 2: dose intragástrica de óleo de milho puro durante a gestação e dose de BPA (5 μg/kg) durante o período de amamentação dos filhotes; Grupo 3: dose intragástrica de óleo de milho durante toda a gestação até o período de desmame dos filhotes. Os filhotes foram eutanasiádos nos períodos de 7 dias (G1=5; G2=5; e G3=4) e 12 dias (G1=7; G2=6; e G3=4) de vida para avaliações morfométricas dos germes dos dentes molares; e aos 60 dias foram eutanasiádos os filhotes (G1=17; G2=11; e G3=6) sendo extraídos os incisivos inferiores para análise do conteúdo elementar na superfície dos esmalte. Para o processamento histológico e análises morfométricas (7 e 12 dias), as cabeças dos ratos foram removidas, fixadas e processadas para inclusão em parafina. Cortes frontais exibindo os primeiros molares superiores foram corados com hematoxilina de Carazzi e eosina (H&E) para mensuração da espessura da matriz de esmalte nas regiões das cúspides e na lateral vestibular. Os incisivos (60 dias) foram submetidos a microscopia eletrônica de varredura (MEV) e espectroscopia por energia dispersiva (EDS) para análise do conteúdo de fósforo, cálcio e carbono. Os dados quantitativos foram comparados por ANOVA e pós-teste de Tukey e Games-Howell, considerando α=0.05. RESULTADOS: Os animais de 7 dias expostos ao BPA (G1 e G2) apresentaram matriz de esmalte com espessuras semelhantes e ambas mais delgadas que o grupo controle (G3) em todas as regiões avaliadas (p<0.036). Aos 12 dias, os animais ao BPA (G1 e G2) apresentaram espessuras semelhantes e ambas mais delgadas que o grupo controle (G3) na área da cúspide (p<0.004). Nos animais de 60 dias, os grupos expostos aos BPA (G1 e G2) não diferiram entre si quanto aos elementos avaliados, sendo ambos menores que o grupo controle (G3) para os elementos fósforo e cálcio (p<0.001). CONCLUSÃO: Os dentes dos animais que foram expostos ao BPA no período gestacional e/ou na amamentação sofreram alterações no conteúdo de cálcio, fósforo e carbono na superfície do esmalte dos dentes incisivos (60 dias) e redução da espessura da matriz de esmalte dos germes dos dentes molares (7 e 12 dias).
Amelogenesis is a process that is sensitive to interference from genetic, traumatic, hormonal factors, drogs and some pollutants. Bisphenol A (BPA) is an endocrine-disrupting chemical that has been suggested as an interference factor in important processes in the perinatal period. OBJECTIVE: Evaluating the development and microstructure of dental enamel in rats from exposure to BPA during pregnancy and breastfeeding. METHODS: After mating and confirmation of pregnancy, six rats (Rattus norvegicus, albinus, Holtzman) were randomly distributed into three groups that received daily, in Group 1: intragastric BPA (5 μg/kg) during pregnancy and breastfeeding period of the puppies (21 days after birth); Group 2: intragastric corn oil during pregnancy and BPA (5 μg/kg) during the puppies’ breastfeeding period; Group 3: intragastric corn oil during pregnancy and breastfeeding period. The puppies were euthanized in the periods of 7 days (G1 = 5; G2 = 5; and G3 = 4) and 12 days (G1 = 7; G2 = 6; and G3 = 4) of life for morphometric evaluations of the molar teeth germs; and at 60 days the puppies were euthanized (G1 = 17; G2 = 11; and G3 = 6) and the lower incisors were extracted for analysis of the elemental content on the enamel surface. For histological processing and morphometric analysis (7 and 12 days), the rats' heads were removed, fixed and processed for inclusion in paraffin. Frontal sections showing the first maxillary molars were stained with Carazzi hematoxylin and eosin (H&E) to measure the thickness of the enamel matrix in the region of the cusps and in the buccal side. The incisors (60 days) were submitted to scanning electron microscopy (SEM) and dispersive energy spectroscopy (EDX) to analyze the content of phosphorus, calcium and carbon. Quantitative data were compared by ANOVA and Tukey and Games-Howell posthoc, considering α = 0.05. RESULTS: In the 7-day animals exposed to BPA (G1 and G2), they had an enamel matrix with similar thicknesses and both were thinner than the control group (G3) in all evaluated regions (p <0.036). At 12 days, BPA animals (G1 and G2) had similar thicknesses and both were thinner than the control group (G3) in the cusp area (p <0.004). In the 60-day animals, the groups exposed to BPA (G1 and G2) did not differ in relation to the evaluated elements, both being smaller than the control group (G3) for the elements phosphorus and calcium (p <0.001). CONCLUSION: The teeth of animals that were exposed to BPA during pregnancy and/or breastfeeding underwent changes in the content of calcium, phosphorus and carbon on the enamel surface of the incisor teeth and reduced thickness of the enamel matrix of the molar teeth germs.
Amelogenesis is a process that is sensitive to interference from genetic, traumatic, hormonal factors, drogs and some pollutants. Bisphenol A (BPA) is an endocrine-disrupting chemical that has been suggested as an interference factor in important processes in the perinatal period. OBJECTIVE: Evaluating the development and microstructure of dental enamel in rats from exposure to BPA during pregnancy and breastfeeding. METHODS: After mating and confirmation of pregnancy, six rats (Rattus norvegicus, albinus, Holtzman) were randomly distributed into three groups that received daily, in Group 1: intragastric BPA (5 μg/kg) during pregnancy and breastfeeding period of the puppies (21 days after birth); Group 2: intragastric corn oil during pregnancy and BPA (5 μg/kg) during the puppies’ breastfeeding period; Group 3: intragastric corn oil during pregnancy and breastfeeding period. The puppies were euthanized in the periods of 7 days (G1 = 5; G2 = 5; and G3 = 4) and 12 days (G1 = 7; G2 = 6; and G3 = 4) of life for morphometric evaluations of the molar teeth germs; and at 60 days the puppies were euthanized (G1 = 17; G2 = 11; and G3 = 6) and the lower incisors were extracted for analysis of the elemental content on the enamel surface. For histological processing and morphometric analysis (7 and 12 days), the rats' heads were removed, fixed and processed for inclusion in paraffin. Frontal sections showing the first maxillary molars were stained with Carazzi hematoxylin and eosin (H&E) to measure the thickness of the enamel matrix in the region of the cusps and in the buccal side. The incisors (60 days) were submitted to scanning electron microscopy (SEM) and dispersive energy spectroscopy (EDX) to analyze the content of phosphorus, calcium and carbon. Quantitative data were compared by ANOVA and Tukey and Games-Howell posthoc, considering α = 0.05. RESULTS: In the 7-day animals exposed to BPA (G1 and G2), they had an enamel matrix with similar thicknesses and both were thinner than the control group (G3) in all evaluated regions (p <0.036). At 12 days, BPA animals (G1 and G2) had similar thicknesses and both were thinner than the control group (G3) in the cusp area (p <0.004). In the 60-day animals, the groups exposed to BPA (G1 and G2) did not differ in relation to the evaluated elements, both being smaller than the control group (G3) for the elements phosphorus and calcium (p <0.001). CONCLUSION: The teeth of animals that were exposed to BPA during pregnancy and/or breastfeeding underwent changes in the content of calcium, phosphorus and carbon on the enamel surface of the incisor teeth and reduced thickness of the enamel matrix of the molar teeth germs.
Descrição
Palavras-chave
Esmalte dentário, Amelogênese, Rato, Dental enamel, Amelogenesis, Rat