Avaliação de sensibilização cutânea: uma abordagem integrada in chemico e in silico
Data
2022-12-08
Autores
Santos, Gabriella Lisboa dos 
Orientadores
Lopes, Patricia Santos
Tipo
Trabalho de conclusão de curso
Título da Revista
ISSN da Revista
Título de Volume
Resumo
A indústria cosmética tem se tornado o centro da atual discussão acerca da experimentação animal. Com os consumidores questionando a validade ética e científica deste método, a crescente rejeição a produtos de beleza testados em animais força as indústrias a encontrar novas abordagens para avaliações de segurança e eficácia. Um desfecho toxicológico importante a ser avaliado em um ingrediente cosmético é o seu potencial de causar dermatite alérgica de contato, isto é, sensibilização cutânea. Ao longo dos últimos anos a OECD formalizou diversos protocolos substituindo, reduzindo ou refinando o uso de animais em diferentes testes de segurança. Com a elucidação das etapas-chave do processo de sensibilização, é possível avaliar o potencial sensibilizante de componentes de cosméticos por meio de diversos tipos de técnicas utilizadas em conjunto, a fim de obter resultados robustos e confiáveis sem a necessidade do modelo animal. Este trabalho propõe uma abordagem inicial de métodos in silico e in chemico utilizando substâncias químicas de ausente (1-butanol) ou conhecido potencial sensibilizante dérmico (2,4-dinitroclorobenzeno e 2,3-butanodiona). A etapa in chemico ou experimental consiste no Ensaio de Reatividade Peptídica Direta (OECD TG 442C), que mimetiza o evento molecular iniciador da via de sensibilização por depleção peptídica. Para o método in silico utilizou-se os softwares ADMET Predictor™ e QSAR Toolbox para obter dados relativos à fisiologia da sensibilização dérmica e reatividade de cada uma das substâncias. A etapa experimental obteve êxito na predição dos potenciais sensibilizantes, as depleções médias (DM) geradas foram muito condizentes com o descrito em literatura para cada substância, sendo o dinitroclorobenzeno um sensibilizante extremo (DM = 57,41%), a 2,3-butanodiona um moderado (DM = 48,99%) e o 1-butanol um não sensibilizante (DM = 4,74%). Houve também boa concordância entre os resultados in chemico e in silico, possibilitando o entendimento dos domínios de reatividade de cada substância. Assim, a estratégia integrada proposta se mostrou útil para o desfecho avaliado e com muitas potencialidades a serem exploradas na avaliação de risco de cosméticos.
Cosmetic industry is the current center of the discussion about animal experimentation. Consumers argue about the ethical and scientific validity of this method and the growing rejection of beauty products tested on animals has forced industry to search new approaches to safety and efficacy assessment. An important endpoint to be evaluated for a cosmetic ingredient is its potential to cause allergic contact dermatitis, i.e. skin sensitization. In the last years, the OECD has formalized several protocols that replace, reduce or refine animals use in some safety tests. With the elucidation of the sensitization key events, it’s already possible to assess cosmetic components sensitizing potential with several types of techniques used together, in order to obtain robust and reliable results without animal models. This work proposes an initial framework composed of in silico and in chemico methods, using substances with no (butanol) or wellknown sensitizing potential (dinitrochlorobenzene and butanedione). The in chemico or experimental step is the Direct Peptide Reacitivity Assay (OECD TG 442C), which simulates the initiating molecular event of the sensitization pathway by peptide depletion. In the in silico method, ADMET Predictor™ and QSAR Toolbox software were used to pursue information about the physiology of skin sensitization and reactivity for each test chemical. The experimental step was successfully in predicting the sensitizing potential, with the average depletion (AD) by the chemicals being very similar with the described in literature: dinitrochlorobenzene was an extreme sensitizer (AD = 57,41%), butanedione was moderated (AD = 48,99%) and butanol a nonsensitizer (AD = 4,74%). There is also good similarity between the in chemico and in silico results, enabling the understanding of the reactivity domains of each substance. Therefore, the proposed integrated strategy proved to be useful for the evaluated endpoint, with many potentialities to be explored in the risk assessment for cosmetics.
Cosmetic industry is the current center of the discussion about animal experimentation. Consumers argue about the ethical and scientific validity of this method and the growing rejection of beauty products tested on animals has forced industry to search new approaches to safety and efficacy assessment. An important endpoint to be evaluated for a cosmetic ingredient is its potential to cause allergic contact dermatitis, i.e. skin sensitization. In the last years, the OECD has formalized several protocols that replace, reduce or refine animals use in some safety tests. With the elucidation of the sensitization key events, it’s already possible to assess cosmetic components sensitizing potential with several types of techniques used together, in order to obtain robust and reliable results without animal models. This work proposes an initial framework composed of in silico and in chemico methods, using substances with no (butanol) or wellknown sensitizing potential (dinitrochlorobenzene and butanedione). The in chemico or experimental step is the Direct Peptide Reacitivity Assay (OECD TG 442C), which simulates the initiating molecular event of the sensitization pathway by peptide depletion. In the in silico method, ADMET Predictor™ and QSAR Toolbox software were used to pursue information about the physiology of skin sensitization and reactivity for each test chemical. The experimental step was successfully in predicting the sensitizing potential, with the average depletion (AD) by the chemicals being very similar with the described in literature: dinitrochlorobenzene was an extreme sensitizer (AD = 57,41%), butanedione was moderated (AD = 48,99%) and butanol a nonsensitizer (AD = 4,74%). There is also good similarity between the in chemico and in silico results, enabling the understanding of the reactivity domains of each substance. Therefore, the proposed integrated strategy proved to be useful for the evaluated endpoint, with many potentialities to be explored in the risk assessment for cosmetics.