Analysis of the Temporal Events in Blood and Tissues Following Fecal Peritonitis in Mice

Background: The kinetics of systemic responses triggered by bacterial peritonitis were analysed in the blood, bronchoalveolar lavage (BAL) and several organs. Materials and Methods: The murine model of cecal ligation and puncture was employed. The parameters were analysed at different periods of time (4 to 72 h). Results: Fecal peritonitis triggered a progressive, but not significant, decline of blood leukocytes between 4 and 6 h, becoming significant at 24 to 48 h (p<0.05). This profile was closely associated with the enhancement of leukocytes both in the abdomen (p<0.05) and in the BAL (p<0.05). A significant abdominal exudation was detected between 4 and 72 h (p<0.01), whereas maximal growth of aerobic bacteria in the blood and lungs was observed 24 and 72 h after. Maximal exudation in the studied tissues occurred at different time points (heart=24 h, spleen and kidney=48 h, liver and lung=72 h). Conclusion: Using this model, evidence of sepsis can be easily measured in different body systems. Severe sepsis with organ dysfunction remains a common surgical problem with a high mortality rate, despite numerous advances in critical care therapy (1). In this scenario, acute lung injury is a primary component, the most important cause of adult respiratory distress syndrome, with a mortality rate of 50% (2-4). In recent decades, research on the pathogenesis of sepsis has been dominated by the assumption that this syndrome is the result of an imbalance between systemic pro- inflammatory reactions and anti-inflammatory responses (5,6). Furthermore, complex interactions between these different mediators produce profound pathophysiological alterations, which ultimately lead to diffuse tissue injury and the progressive deterioration of the function of several organs (7). The main reason to further explore the temporal relationship of the sequence of events that are triggered by sepsis remains the fact that, although significant progress has been made in recent years in the field of inflammation, an effective therapeutic approach has not yet been developed (8). To analyse the different aspects of both local and systemic body responses in sepsis, the murine model of cecal ligation and puncture (CLP) is a clinically relevant model (9). In the present work, we further analyse some of the systemic inflammatory reactions that are trigged by sepsis caused by fecal peritonitis in close association with abdominal cavity events. Thus, the following parameters were addressed: 1) the kinetics of leukocyte and fluid changes induced by fecal peritonitis in both abdominal cavity and in bronchoalveolar lavage; 2) the degree of exudation in different organs (spleen, heart, liver, kidney and lung); and 3) aerobic bacterial growth in the abdominal exudate, blood, kidneys and lungs.