Atividade proteolítica e degradação da matriz da dentina bovina e humana
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Data
2017-05-12
Autores
Inagati, Cristiane Mayumi [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Dentes bovinos têm sido utilizados como substitutos aos dentes humanos, especialmente em pesquisas sobre adesão. Entretanto, ainda não foi demonstrada se a degradação do colágeno de ambos os substratos ocorre na mesma intensidade/velocidade. Portanto, esse estudo comparou a atividade de metaloproteinases da matriz (MMPs) e a degradação da matriz dentinária de dentes bovinos versus humanos. A coroa de dentes humanos e bovinos foram seccionadas para a obtenção de espécimes de dentina (0,5x1,0x4,0 mm). Todos os espécimes (n=30/tipo de dente) foram completamente desmineralizados em ácido fosfórico. Quinze espécimes foram aleatoriamente selecionados para a análise da atividade total de MMPs por método colorimétrico, e os restantes foram utilizados para a análise de perda de massa seca em balança microanalítica. Concluídas as análises iniciais, os espécimes foram armazenados em saliva e as análises, perda de massa seca e MMPs, foram repetidas após 7, 14 e 21 dias. Em cada período, a saliva foi coletada para a análise da liberação de hidroxiprolina por meio de teste colorimétrico. Os dados foram submetidos aos testes de Friedman, Wilcoxon para medidas repetidas e Mann-Whitney (p<0,05). A atividade inicial de MMPs foi similar dentre os dois substratos, com redução significante em função do tempo, especialmente após 7 dias de armazenamento. Aos 7, 14 e 21 dias de análise, a atividade de MMPs foi mais intensa para a dentina bovina. Aos 7 dias houve elevada liberação de hidroxiprolina para ambos os substratos, sendo que maiores valores foram encontrados para a dentina bovina. Aumento da perda de massa seca também foi observado em função do tempo. Entretanto, diferença significante entre os dois substratos foi detectada apenas aos 21 dias. Em conclusão, embora a velocidade da atividade proteolítica e de liberação de hidroxiprolina tenha sido similar para ambos os substratos, a intensidade desses eventos foi maior para a dentina bovina.
Bovine teeth have been often used as a substitute for human teeth in studies about enamel and dentin adhesion. However, it has not yet been shown if the degradation of collagen of both substrates occurs at the same intensity and rate. Therefore, this study compared the total activity of matrix metalloproteinases (MMPs) and the degradation rate of dentin matrix from bovine versus human teeth. The crowns of human and bovine teeth were sectioned to obtain specimens of dentin (0.5x1.0x4.0mm). All specimens (n=30/tooth type) were completely demineralized in phosphoric acid. Fifteen specimens were randomly selected for the total MMPs activity analysis by a colorimetric method, while the remaining specimens were used to determine the loss of dry mass in a microanalytical balance. Once the initial analyses were concluded, the specimens were stored in saliva-like solution, and both analyzes, dry mass and MMPs activity, were repeated after 7, 14 and 21 days. In each period, the saliva was collected to determine the amount of hydroxyproline released by means of a colorimetric assay. The data were submitted to Friedman, repeated-measures Wilcoxon and Mann-Whitney tests (p<0.05). Similar initial MMP activity was seen between the two substrates, with a significant reduction over time, especially after 7 days. At 7, 14 and 21 days, bovine dentin had a higher proteolytic activity. After 7 days, there was a high hydroxyproline release for both substrates, with significantly higher amounts seen for the bovine dentin. Increased dry mass loss was also observed as a function of time. However, a significant difference between both substrates was detected only after 21 days. In conclusion, although the rate of proteolytic activity and hydroxyproline release were similar for both substrates, the intensity of these events were greater for the bovine dentin.
Bovine teeth have been often used as a substitute for human teeth in studies about enamel and dentin adhesion. However, it has not yet been shown if the degradation of collagen of both substrates occurs at the same intensity and rate. Therefore, this study compared the total activity of matrix metalloproteinases (MMPs) and the degradation rate of dentin matrix from bovine versus human teeth. The crowns of human and bovine teeth were sectioned to obtain specimens of dentin (0.5x1.0x4.0mm). All specimens (n=30/tooth type) were completely demineralized in phosphoric acid. Fifteen specimens were randomly selected for the total MMPs activity analysis by a colorimetric method, while the remaining specimens were used to determine the loss of dry mass in a microanalytical balance. Once the initial analyses were concluded, the specimens were stored in saliva-like solution, and both analyzes, dry mass and MMPs activity, were repeated after 7, 14 and 21 days. In each period, the saliva was collected to determine the amount of hydroxyproline released by means of a colorimetric assay. The data were submitted to Friedman, repeated-measures Wilcoxon and Mann-Whitney tests (p<0.05). Similar initial MMP activity was seen between the two substrates, with a significant reduction over time, especially after 7 days. At 7, 14 and 21 days, bovine dentin had a higher proteolytic activity. After 7 days, there was a high hydroxyproline release for both substrates, with significantly higher amounts seen for the bovine dentin. Increased dry mass loss was also observed as a function of time. However, a significant difference between both substrates was detected only after 21 days. In conclusion, although the rate of proteolytic activity and hydroxyproline release were similar for both substrates, the intensity of these events were greater for the bovine dentin.
Descrição
Palavras-chave
Dentina, Metaloproteases, Hidroxiprolina