Inativação fotodinâmica mediada pela curcumina veiculada em sistema precursor de cristal líquido sobre biofilme dental formado in situ
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Data
2019-05-08
Autores
Reina, Bárbara Donadon
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Universidade Estadual Paulista (Unesp)
Resumo
Estima-se que mais de 60% das infecções humanas são originadas pela presença de biofilmes. A placa dentária é o biofilme mais antigo descrito na literatura epode ser composta por diferentes gêneros e espécies, com destaque para a atuação de Lactobacillus spp, Streptococcus do grupo mutans e Candida albicans. A Inativação Fotodinâmica (do inglês, Photodynamic Inactivation - PDI) vem sendo apontada como modalidade terapêutica promissora para a inativação de microrganismos bucais visando sanar os problemas relacionados com a resistência dos microrganismos e não promover efeitos colaterais adversos. Estudos prévios conduzidos dentro e fora de nosso grupo de pesquisa mostraram que a curcumina possui grande potencial como fotossensibilizador para a PDI. Apesar disso, a curcumina apresenta baixa solubilidade em soluções aquosas e por isso esse estudo se propôs a avaliar a eficácia antimicrobiana da PDI, utilizando a curcumina veiculada em sistema precursor de cristal líquido (SPCL), em biofilmes dentais formados in situ. Esse sistema possui diversas vantagens descritas na literatura, como sua bioadesividade no local de ação, liberação controlada e biocompatibilidade. No entanto, nenhum estudo avaliou o sistema precursor de cristal líquido veiculando curcumina para ação fotodinâmica em biofilmes dentais. Este estudo contou com 30 voluntários que utilizaram dispositivos orais palatinos, contendo blocos de esmalte bovino, por 48 horas para a formação de biofilme in situ. Após esse período, os blocos de esmalte foram aleatorizados em dois grupos e metade deles foi alocada no grupo controle (somente SPCL vazio) e a outra metade foi incubada no escuro, imersa em curcumina veiculada no SPCL, e depois iluminada com um LED de luz azul (grupo PDI). Passados os tratamentos, foi determinada a UFC/ml de cada grupo, em meios de cultura preditivos para espécies de Streptococcus do grupo mutans, Candida spp, Lactobacillus e acidúricos e microbiota total específica para as condições de cultivo deste estudo. Após análise multivariada, foi observado que o tratamento teve um efeito de elevada dimensão e altamente significativo sobre a viabilidade microbiana. Procedeu-se então à ANOVA univariada, a qual revelou redução significativa nos valores de log10(UFC/mL) nos grupos PDI em relação ao grupo controle, para todas as condições de cultivo. Foram obtidas reduções médias na ordem de 2,08; 1,34; 1,80 e 1,54 log10 para Chromagar Candida, MRS, Müller Hinton e Mitis Salivarius respectivamente. Além disso, os dados descritivos sugerem haver certa variação do efeito da PDI entre diferentes indivíduos. Esse fato foi confirmado com os resultados da análise por modelagem hierárquica. Em conclusão, a Inativação Fotodinâmica mediada pela curcumina, veiculada em SPCL foi eficaz em promover redução na viabilidade dos microrganismos presentes nos biofilmes in situ, a qual parece ser uma técnica promissora para a inativação de biofilmes dentais e para estudos clínicos futuros.
It is estimated that more than 60% of human infections are originated by the presence of biofilms. The dental plaque, reported as the oldest biofilm, can be composed of many different species, highlighting Lactobacillus spp, Streptococcus mutans and Candida albicans. Photodynamic Inactivation (PDI) has been suggested as a promising therapeutic modality for the inactivation of oral microorganisms, in order to overcome the problems related to microorganism resistance and prevent adverse side effects. Previous studies have shown that curcumin is a promising photosensitizer for PDI. Nevertheless, curcumin has low solubility in aqueous solutions, therefore, this study proposed to evaluate the antimicrobial efficacy of the PDI, using the curcumin in a liquid crystal precursor system (LCPS), in dental biofilms formed in situ. This system has several advantages described in the literature, such as its bioadhesiveness at the site of action, controlled release and biocompatibility. However, no study evaluated the LCPS carrying curcumin for photodynamic action on biofilms formed in situ. This study included 30 volunteers who used oral palatal devices containing bovine enamel blocks for 48 hours for in situ biofilm formation. After that period, the enamel blocks were randomized into two groups: i. control group (empty LCPS only); ii. PDI (immersed in LCPS with curcumin in the dark and then illuminated with a blue light LED) incubated, (PDI group). After the treatments, the CFU/ml of each group was determined in culture media presumptive for Streptococci mutans, Candida spp, Lactobacillus spp. and aciduric species, and total microbiota, specific to the culture conditions for this study. Multivariate analysis showed that the treatment had a large and highly significant effect on microbial viability. Univariate ANOVA was then performed, which revealed a significant reduction on log10(CFU/mL) values in the PDI groups, compared to the control group, for all the culture conditions. Mean reductions were obtained in the order of 2,08; 1,34; 1,80 e 1,54 log10 for Chromagar Candida, MRS, Müller Hinton e Mitis Salivarius respectively. In addition, the descriptive data suggest that there was some variation of the effect of the PDI between different individuals. This fact was confirmed by the results of hierarchical modeling analysis. In conclusion, curcumin-mediated photodynamic inactivation in LCPS was effective in reducing the viability of microorganisms present in in situ biofilms, which seems to be a promising technique for the inactivation of dental biofilms and for future clinical studies.
It is estimated that more than 60% of human infections are originated by the presence of biofilms. The dental plaque, reported as the oldest biofilm, can be composed of many different species, highlighting Lactobacillus spp, Streptococcus mutans and Candida albicans. Photodynamic Inactivation (PDI) has been suggested as a promising therapeutic modality for the inactivation of oral microorganisms, in order to overcome the problems related to microorganism resistance and prevent adverse side effects. Previous studies have shown that curcumin is a promising photosensitizer for PDI. Nevertheless, curcumin has low solubility in aqueous solutions, therefore, this study proposed to evaluate the antimicrobial efficacy of the PDI, using the curcumin in a liquid crystal precursor system (LCPS), in dental biofilms formed in situ. This system has several advantages described in the literature, such as its bioadhesiveness at the site of action, controlled release and biocompatibility. However, no study evaluated the LCPS carrying curcumin for photodynamic action on biofilms formed in situ. This study included 30 volunteers who used oral palatal devices containing bovine enamel blocks for 48 hours for in situ biofilm formation. After that period, the enamel blocks were randomized into two groups: i. control group (empty LCPS only); ii. PDI (immersed in LCPS with curcumin in the dark and then illuminated with a blue light LED) incubated, (PDI group). After the treatments, the CFU/ml of each group was determined in culture media presumptive for Streptococci mutans, Candida spp, Lactobacillus spp. and aciduric species, and total microbiota, specific to the culture conditions for this study. Multivariate analysis showed that the treatment had a large and highly significant effect on microbial viability. Univariate ANOVA was then performed, which revealed a significant reduction on log10(CFU/mL) values in the PDI groups, compared to the control group, for all the culture conditions. Mean reductions were obtained in the order of 2,08; 1,34; 1,80 e 1,54 log10 for Chromagar Candida, MRS, Müller Hinton e Mitis Salivarius respectively. In addition, the descriptive data suggest that there was some variation of the effect of the PDI between different individuals. This fact was confirmed by the results of hierarchical modeling analysis. In conclusion, curcumin-mediated photodynamic inactivation in LCPS was effective in reducing the viability of microorganisms present in in situ biofilms, which seems to be a promising technique for the inactivation of dental biofilms and for future clinical studies.
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Palavras-chave
Fotoquimioterapia, Curcumina, Placa dentária, Cristais líquidos, Photochemotherapy, Curcumin, Dental plaque, Liquid crystals