Influência do tolueno como contaminante dos solos na imunopatogenia de Sporothrix schenckii
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Data
2018-05-30
Autores
Téllez Martínez, Damiana
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Universidade Estadual Paulista (Unesp)
Resumo
A esporotricose é uma micose subcutânea emergente que acomete animais e humanos, causada por espécies patogênicas do fungo Sporothrix schenckii senso lato. A doença, distribuída em todo o mundo, é mais freqüente na América Latina e países como Brasil, Uruguai, Peru e Colômbia constituem áreas endêmicas. No Brasil, a doença tornou-se um problema de saúde em razão do aumento de casos, manifestando-se com uma intrigante transmissão zoonótica por gatos. Os fatores ambientais extremos modificam a fisiologia dos microrganismos, permitindo sua sobrevivência e induzendo mudanças na virulência dos fungos patógenos com incidência direta no sistema imune. O tolueno encontra-se dentre os principais contaminantes dos solos como consequencia dos derramamentos de gasolinas, resíduos da indústria, dentre outras fontes de poluição, porém, o efeito deste contaminante sobre a virulência do fungo S. schenckii ainda não foi elucidado. Neste estudo foi avaliado o crescimento e a virulência de S. schenckii quando exposto ao tolueno. O fungo sobreviveu a 0,01 e 0,10% (vol/vol) de tolueno, sendo a população reduzida até 17,5 e 5,4%, respectivamente. O consumo de tolueno na concentração 0,01% mostrou uma redução de 26% após 48 horas. As enzimas superóxido dismutase e catalase nos fungos expostos ao tolueno foram altamente expressas, o qual permitiu uma maior remoção das espécies reativas de oxigênio intracelular nos fungos expostos, e uma menor sensibilidade à exposição de H2O2 sendo que resistiram até 62,5 mM, entretanto, àqueles não crescidos em tolueno cresceram somente até 31,25 mM. A presença de melanossomas em conídios expostos ao tolueno foi significativamente maior. A virulência avaliada em camundongos Balb/c infectados com fungos expostos a 0,10% de tolueno pela via intraperitoneal apresentou maior carga fúngica em baço e fígado e mais alta produção de óxido nítrico, IL-1β, TNF-α e IL-10 em macrófagos peritoneais. A resposta à infecção pela via subcutânea mostrou também maior carga fúngica no fígado e pele dos animais infectados com fungo expostos a 0,10%, e revelou uma marcada reação inflamatória granulomatosa como resposta a uma maior virulência desses fungos demonstrados por estudos anatomopatologico. A resposta imunológica associada mostrou uma elevação dos linfócitos Th1/Th17 e Tregs no soro por meio da liberação de mediadores da imunidade específica: IFNƔ, IL-17 e IL-10. No modelo subcutâneo também se observou um aumento dos níveis de linfócitos do perfil Th1 e Th1/Th17 com fenotipagem CD3+CD4+CD25+IFNɣ e CD3+CD4+CD25+ IFNɣ/CD3+ CD4+ CD25+ IL-17; tais modificações das populaçoes linfocitarias tiveram uma expresão na citocinas do padrão Th1 (IL-2, IFNɣ, TNF), Th2 (IL-4, IL-6, IL-10) e Th17 (IL-17). Também se observou um aumento das células Tregs com fenótipo CD3+CD4+CD25+Foxp3+ e a citocina antinflamatória IL-10 como reflexo da necessidade de compensar a excessiva resposta inflamatória causada pela virulência do fungo. Os resultados mostram o aumento da virulência de S. schenckii após a exposição ao tolueno, o que corrobora a hipótese de que influências ambientais produzem mudanças na virulência fúngica e constitui uma maneira de explicar, pelo menos em parte, o surgimento de possíveis surtos em regiões altamente poluídas.
Sporotrichosis is an emerging subcutaneous mycosis that affects animals and humans, caused by pathogenic species of the fungus Sporothrix schenckii senso lato. It is distributed worldwide, being more frequent in Latin America and the countries of Brazil, Uruguay, Peru, and Colombia constitute endemic areas. In Brazil, the disease has become a health problem due to the increase in cases, manifested with an intriguing zoonotic transmission by cats. Extreme environmental factors modify the physiology of microorganisms, allowing their survival and inducing changes in the virulence of pathogenic fungi with direct incidence in the immune system. Toluene is one of the main contaminants of soils as a consequence of the spills of gasolines, industrial waste, among other sources of pollution, but the effect of this contaminant on the virulence of the S. schenckii fungus has not been elucidated yet. This study evaluated the growth and virulence of S. schenckii when exposed to toluene. The fungus survived 0.01 and 0.10% (vol / vol) toluene, with the population reduced to 17.5 and 5.4%, respectively. The consumption of toluene in the concentration 0.01% showed a reduction of 26% after 48 hours. The enzymes superoxide dismutase and catalase in the toluene-exposed fungi were highly expressed, which allowed a greater removal of of intracellular oxygen reactive species in the exposed fungi, and a lower sensitivity to the exposure of H2O2 being resistant up to 62.5 mM, however, those not grown in toluene grew only up to 31.25 mM. The presence of melanosomes in conidia exposed to toluene was significantly higher.Virulence evaluated in Balb/c mice infected with fungi exposed to 0.10% of toluene by the intraperitoneal route presented higher fungal load in spleen and liver and higher production of nitric oxide, IL-1β, TNF-α and IL-10 in peritoneal macrophages. The response to infection by the subcutaneous route also showed a greater fungal load on the liver and skin of animals infected with fungus exposed to 0.10%, and showed a marked granulomatous inflammatory reaction in response to a higher virulence of these fungi demonstrated by anatomopathological studies. The associated immune response showed an increase of Th1/Th17 lymphocytes and Tregs in serum by the release of mediators of the specific immunity: IFNƔ, IL-17 and IL-10. In the subcutaneous model, the levels of lymphocytes of the Th1 and Th1/ Th17 profile were also observed with phenotyping CD3+CD4+CD25+IFNɣ and CD3+CD4+CD25+ IFNɣ/CD3+ CD4+ CD25+ IL-17; such modifications of the lymphocyte populations had an expression in Th1 (IL-2, IFNɣ, TNF), Th2 (IL-4, IL-6, IL-10) and Th17 (IL-17) cytokines. An increase of Treg cells with CD3+CD4+CD25+Foxp3+ phenotype and IL-10 anti-inflammatory cytokine was also observed as a reflection of the need to compensate for the excessive inflammatory response caused by the virulence of the fungus. The results show the increased virulence of S. schenckii after exposure to toluene, which corroborates the hypothesis that environmental influences produce changes in fungal virulence and is a way of explaining, at least in part, the emergence of possible outbreaks in regions highly polluted.
Sporotrichosis is an emerging subcutaneous mycosis that affects animals and humans, caused by pathogenic species of the fungus Sporothrix schenckii senso lato. It is distributed worldwide, being more frequent in Latin America and the countries of Brazil, Uruguay, Peru, and Colombia constitute endemic areas. In Brazil, the disease has become a health problem due to the increase in cases, manifested with an intriguing zoonotic transmission by cats. Extreme environmental factors modify the physiology of microorganisms, allowing their survival and inducing changes in the virulence of pathogenic fungi with direct incidence in the immune system. Toluene is one of the main contaminants of soils as a consequence of the spills of gasolines, industrial waste, among other sources of pollution, but the effect of this contaminant on the virulence of the S. schenckii fungus has not been elucidated yet. This study evaluated the growth and virulence of S. schenckii when exposed to toluene. The fungus survived 0.01 and 0.10% (vol / vol) toluene, with the population reduced to 17.5 and 5.4%, respectively. The consumption of toluene in the concentration 0.01% showed a reduction of 26% after 48 hours. The enzymes superoxide dismutase and catalase in the toluene-exposed fungi were highly expressed, which allowed a greater removal of of intracellular oxygen reactive species in the exposed fungi, and a lower sensitivity to the exposure of H2O2 being resistant up to 62.5 mM, however, those not grown in toluene grew only up to 31.25 mM. The presence of melanosomes in conidia exposed to toluene was significantly higher.Virulence evaluated in Balb/c mice infected with fungi exposed to 0.10% of toluene by the intraperitoneal route presented higher fungal load in spleen and liver and higher production of nitric oxide, IL-1β, TNF-α and IL-10 in peritoneal macrophages. The response to infection by the subcutaneous route also showed a greater fungal load on the liver and skin of animals infected with fungus exposed to 0.10%, and showed a marked granulomatous inflammatory reaction in response to a higher virulence of these fungi demonstrated by anatomopathological studies. The associated immune response showed an increase of Th1/Th17 lymphocytes and Tregs in serum by the release of mediators of the specific immunity: IFNƔ, IL-17 and IL-10. In the subcutaneous model, the levels of lymphocytes of the Th1 and Th1/ Th17 profile were also observed with phenotyping CD3+CD4+CD25+IFNɣ and CD3+CD4+CD25+ IFNɣ/CD3+ CD4+ CD25+ IL-17; such modifications of the lymphocyte populations had an expression in Th1 (IL-2, IFNɣ, TNF), Th2 (IL-4, IL-6, IL-10) and Th17 (IL-17) cytokines. An increase of Treg cells with CD3+CD4+CD25+Foxp3+ phenotype and IL-10 anti-inflammatory cytokine was also observed as a reflection of the need to compensate for the excessive inflammatory response caused by the virulence of the fungus. The results show the increased virulence of S. schenckii after exposure to toluene, which corroborates the hypothesis that environmental influences produce changes in fungal virulence and is a way of explaining, at least in part, the emergence of possible outbreaks in regions highly polluted.
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Palavras-chave
Sporothrix schenckii, Esporotricose, Virulência, Tolueno, Resposta imune, Superóxido dismutase, Contaminação ambiental, Meio ambiente, Sporotrichosis, Virulence, Toluene, Immune response, Superoxide dismutase, Environmental pollution, Environment