Serial Changes of CD4+CD25+FoxP3+ Regulatory T Cell in Canine Model of Sepsis Induced by Endotoxin

Regulatory T cells (Tregs) suppress the immune system and maintain the homeostasis of the immune system in healthy dogs. In septic patients, the percentage of circulating Tregs is increasing, which may cause the sepsis-induced immunosuppression. This study was performed to investigate the changes of the percentage of Tregs in total lymphocytes of the peripheral blood in the experimental canine endotoxemia model. The animals injected with a high dose lipopolysaccharide (LPS) induced severe leukopenia followed by leukocytosis, but the total lymphocytes number was relatively consistent. As a result of flow cytometric analysis, the percentage of Tregs in total lymphocytes of the peripheral blood was 8.45 ± 1.30% (day 0), and it temporarily decreased 2.54 ± 1.16% (day 1) and increased continuously until the end of the experiment (14.34 ± 4.10% on day 3 and 25.70 ± 7.39% on day 7), respectively. This study provides basic information in physiologic and immunologic changes in Tregs in dogs with sepsis model.