Mediação de respostas imunes e do sistema de defesa antioxidante pelo cortisol em pacu (Piaractus mesopotamicus)
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2017-04-07
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Universidade Estadual Paulista (Unesp)
Resumo
O objetivo deste trabalho foi avaliar se o sistema imune inato e o sistema antioxidante hepático são mediados pelo cortisol circulante, em condições de elevação exógena e endógena do hormônio em pacu. Os peixes foram submetidos aos tratamentos: alimentados com ração comercial RC controle (C); alimentados com RC contendo 400 mg de hidrocortisona / kg (HC); expostos a captura por 2 minutos seguida de exposição aérea por 4 minutos (E). No dia da amostragem, os grupos C e HC foram alimentados com a respectiva ração e amostrados 1, 3, 6, 24 e 72 horas depois (n=9), enquanto o grupo E foi alimentado com RC, no mesmo horário dos outros grupos, em seguida exposto ao estressor e amostrado 1, 3, 6, 24 e 72 horas depois. Os peixes tiveram sangue, fígado e baço coletados. No sangue foram determinadas: a concentração de cortisol, glicose, atividade respiratória de leucócitos ARL, concentração sérica de lisozima (CSL) e atividade hemolítica do sistema complemento (AHC). O fígado foi utilizado para determinação da atividade das enzimas catalase (CAT) e glutationa peroxidase (GPx). O baço foi utilizado para cálculo do índice esplenossomático e análise histológica para observação de polpa branca, polpa vermelha, melanomacrófagos e centros de melanomacrófagos. Os resultados obtidos demonstraram que o estresse exógeno e endógeno, de modo geral, elevaram as concentrações sanguíneas de cortisol e glicose. Inicialmente (3 horas), o estresse de manejo aumentou a ARL, mas de modo geral a elevação do cortisol foi associada a redução da ARL e da AHC, bem como da atividade das enzimas GPx e CAT. O estresse de manejo, adicionalmente, causou o aparecimento de melanomacrófagos e centros de melanomacrófagos no baço, sugerindo danos celulares neste órgão linfoide.
The aim of this study was to evaluate if the innate immune system and the hepatic antioxidant system are mediated by circulating cortisol, under conditions of exogenous and endogenous elevation of the hormone in pacu. The fish were submitted to the treatments: fed with commercial RC fed control (C); fed with RC containing 400 mg hydrocortisone / kg feed (HC); exposed to capture for 2 minutes followed by air exposure for 4 minutes (E). On the sampling day, the groups C and HC were fed with the respective feed and sampled 1, 3, 6, 24 and 72 hours later (n= 9), while group E was fed as the other groups, then exposed to the stressor and sampled 1, 3, 6, 24 and 72 hours later. The fish had blood, liver and spleen collected. In the blood it were determined: the concentration of cortisol, glucose, respiratory activity of leukocytes ARL, serum concentration of lysozyme (CLS) and complement haemolytic activity (ACH). The liver was used to determine the activity of the enzymes catalase (CAT) and glutathione peroxidase (GPx). The spleen was used to calculate the splenosomatic index and histological analysis for observation of white pulp, red pulp, melanomacrophages and melanomacrophage centers. The results obtained demonstrated that exogenous and endogenous stress, in general, increased blood concentrations of cortisol and glucose. Initially (3 hours), the stressful handling increased ARL, but in general the elevation of cortisol was associated with a reduction of ARL and AHC, as well as the activity of the GPx and CAT enzymes. The stressful handling additionally caused the appearance of melanomacrophages and melanomacrophage centers in the spleen, suggesting cellular damage in this lymphoid organ.
The aim of this study was to evaluate if the innate immune system and the hepatic antioxidant system are mediated by circulating cortisol, under conditions of exogenous and endogenous elevation of the hormone in pacu. The fish were submitted to the treatments: fed with commercial RC fed control (C); fed with RC containing 400 mg hydrocortisone / kg feed (HC); exposed to capture for 2 minutes followed by air exposure for 4 minutes (E). On the sampling day, the groups C and HC were fed with the respective feed and sampled 1, 3, 6, 24 and 72 hours later (n= 9), while group E was fed as the other groups, then exposed to the stressor and sampled 1, 3, 6, 24 and 72 hours later. The fish had blood, liver and spleen collected. In the blood it were determined: the concentration of cortisol, glucose, respiratory activity of leukocytes ARL, serum concentration of lysozyme (CLS) and complement haemolytic activity (ACH). The liver was used to determine the activity of the enzymes catalase (CAT) and glutathione peroxidase (GPx). The spleen was used to calculate the splenosomatic index and histological analysis for observation of white pulp, red pulp, melanomacrophages and melanomacrophage centers. The results obtained demonstrated that exogenous and endogenous stress, in general, increased blood concentrations of cortisol and glucose. Initially (3 hours), the stressful handling increased ARL, but in general the elevation of cortisol was associated with a reduction of ARL and AHC, as well as the activity of the GPx and CAT enzymes. The stressful handling additionally caused the appearance of melanomacrophages and melanomacrophage centers in the spleen, suggesting cellular damage in this lymphoid organ.
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Estresse, Cortisol, Exógeno, Endógeno, Oxidation, Immunology, Spleen