Efecto del ejercicio agudo sobre la expresión del receptor tipo Toll-4 y los mecanismos inflamatorios en corazón de rata / Effect of an acute exercise bout on Toll-like receptor 4 and inflammatory mechanisms in rat hear

Background: Toll like receptor 4 (TLR-4) is a protein located in the cell membrane with an important function in the immune response of the organism. Its activation decreases heart contractility and activates nuclear transcription factor kappa B (NF-kB ). This in turn, increases the synthesis of different pro-inflammatory cytokines and the inducible enzyme nitric oxide (iNOS), which plays an important role in the inflammatory processes when nitric oxide production is enhanced. Aim: To determine if, after one session of acute exercise, expression of TLR-4 and iNOS, and activation of NF-kB are induced in rat cardiac tissue. Material and Methods: Exercise and control groups of eight male Wistar rats each, were studied. The exercise group was subjected to an acute exercise bout lasting one hour. After the exercise, the heart was excised to measure the expression of iNOS and TLR-4 genes by quantitative polyme-rase chain reaction, NF-kB activation by electrophoretic mobility shift assay (EMSA) and p50 by Western blot. Results: After exercise, there was an increase in TLR-4 and of iNOS mRNA levels (+46.7 and +74.3% respectively). NF-kB activation and the nuclear expression of its p50 subunit also increased significantly (+240 and +306% respectively). Conclusions: Increased expression of TLR4 following a session of acute exercise may contribute to the activation of the NF-kB signaling route, promoting the synthesis of nitric oxide, which could influence negatively the cardiac response to high intensity physical exercise.

Standardization of procalcitonin, C-reactive protein and lactate levels in pigs submitted to laparotomy / Padronização dos níveis de procalcitonina, proteína C- reativa e lactato em suínos submetidos à laparotomia

This study was undertaken to determine the procalcitonin, C-reactive protein and lactate levels in pigs anesthetized and submitted to laparotomy during 5 hours. A total of 05 landrace pigs with 3 months of age and weighing 26 kg were used. After a midline xiphopubic laparotomy, the procalcitonin, C-reactive protein (CRP) and lactate levels were measured at intervals of 60 minutes for 5 hours with samples taken from the jugular vein. The procalcitonin value remained below 0.05 µg. The CRP values were between 6.7 and 8.3 and lactate levels remained between 2.9 and 3.7 for the confidence interval of 95%. We conclude thtat in pigs submitted to laparotomy for 5 hours, the procalcitonin levels did not exceed 0.05 ng / mL. The C-reactive protein and lactate levels were between 6.7 and 8.3 mg / L and 2.9 and 3.7 mg / d, respectively. These data allowed reducing the number of animals.

Este estudo objetivou definir os níveis de procalcitonina, proteína-c reativa (PCR) e lactato em porcos anestesiados e submetidos à laparotomia mediana por 5 horas fornecendo aos pesquisadores um modelo estabelecido para futuras pesquisas sobre estes mediadores em que se necessite realizar laparotomia em patologias experimentais da cavidade abdominal, reduzindo assim o número de animais utilizados. Após a indução anestésica com tiopental, os animais foram posicionados em decúbito dorsal e realizada a dissecção e canulação da veia jugular para as coletas das amostras. Os níveis de procalcitonina, proteína-c reativa e lactatemia foram mensurados em intervalos de 60 minutos por 5 horas com amostras colhidas da veia jugular. As avaliações da procalcitonina não revelaram aumento durante nenhum dos tempos. Todas se mantiveram com valor abaixo de 0,05 µg. Os valores do PCR ficaram entre 6,7085 e 8,2915 e os valores de lactato permaneceram entre 2,8594 e 3,7406 para o intervalo de confiança de 95%. Conclui-se que suínos submetidos à laparotomia mediana por 5 horas não apresentam alterações nos valores de procalcitonina, podendo então, futuras pesquisas que se utilizarem desta proteína de fase aguda adotar o valor acima de 0,05 ng/mL como referência. Em relação à proteína-c reativa, encontramos valores entre 6,7 e 8,3 mg/L e o lactato entre 2,9 e 3,7 mg/dL. Futuras pesquisas que utilizarem suínos, como modelo experimental de patologias adotando a laparotomia mediana, poderão considerar estes valores como referência. Desta forma, podemos diminuir o número de animais, reduzindo o impacto perante a sociedade e o valor financeiro destes estudos.