Content area
Full Text
1. Introduction
Sepsis is characterized by an inflammatory reaction as a consequence of immune system response to bacterial infection [1, 2]. The immune system has an important role in the pathogenesis of sepsis, which may cause tissue damage and lead to organic failure [3, 4]. The main process involves the activation of inflammatory cells such as leukocytes, tissue macrophages, dendritic cells, and eosinophils [5]. The exacerbated activation of innate immune response is one of the main components involved in the physiopathology of sepsis, which can be identified by increased proinflammatory factors after infection [6].
The membrane bound enzyme ectonucleoside triphosphate diphosphohydrolase (NTPDase; CD39; E.C. 3.6.1.5) modulates adenine nucleotides level, which are fundamental to the modulation of immune responses [7]. The enzymes of this family are widely distributed in animal tissues and represent the main ectoenzyme expressed by endothelial cells and muscle cells of the circulatory system [8, 9]. Under physiological conditions, the nucleotides are present in the extracellular environment in low concentrations, usually nanomolar, but may be found up to micromolar levels [10]. It is known that extracellular ATP, for example, when in micromolar concentrations, can induce the formation of pores in the cell membranes, resulting in osmotic changes [11], and it can also induce two antagonistic effects: cell proliferation, when in low concentrations, and cell death, when in high concentrations [10].
Considering the involvement of adenine nucleotides hydrolysis in the modulation of immune system and the participation of immune response in sepsis, the purpose of this study was to evaluate the hydrolysis of ATP and ADP in lymphocytes from rats with induced sepsis.
2. Materials and Methods
2.1. Chemicals
Adenosine 5′-triphosphate disodium salt (ATP), adenosine 5′-diphosphate sodium salt (ADP), bovine serum albumine, Trizma base, Trypan Blue solution, and Coomassie Brilliant Blue G were obtained from Sigma-Aldrich (St. Louis, MO, USA). Ficoll-Hypaque (Lymphoprep) was purchased from Nycomed Pharma (Oslo, Norway). Physiological solution (0.9 g NaCl/100 mL distilled water) was obtained from Fresenius KABI (Brazil). K2HPO4 was purchased from Reagen (Brazil). All chemicals used in the experiments were of analytical grade and of the highest purity.
2.2. Animals
Male and female Wistar rats of 200–300 g bodyweight were used for all experiments, which were performed in accordance with the guidelines of Committee on Care and Use...