The imbalance between regulatory and IL-17-secreting CD4+T cells in multiple-trauma rat

Background: It has been well recognised that a deficit of numbers and function of CD4(+)CD25(+)Foxp3(+) cells (Treg) is attributed to the development of auto-immune diseases, inflammatory diseases, tumour and rejection of transplanted tissue; however, there are controversial data regarding the suppressive effect of Treg cells on the T-cell response in auto-immune diseases. Additionally, interleukin-17 (IL-17)producing cells (Th17) have a pro-inflammatory role. The balance between Th17 and Treg may be essential for maintaining immune homeostasis and has long been thought as one of the important factors in the development/prevention of auto-immune diseases, inflammatory diseases, tumour and rejection of transplanted tissue, but their role in multiple trauma remains unclear. Objective: This study aims to investigate whether an imbalance of Treg and Th17 effector cells is characteristic of rats suffering from multiple trauma. Methods and subjective: Sixty Sprague-Dawley (SD) rats were randomly divided into three groups. The control group (n = 20, group I) no received procedures (normal). The sham group (n = 20, group II) only received anaesthesia, cannulation and observation. The bilateral femoral shaft fractures with haemorrhagic shock groups (n = 20, group III). Rats in groups II and III were killed at the end of 4 h after models were established. Peripheral blood samples were collected for assessment of Treg cells, Th17 cells and cytokines (IL-17, IL-6, IL-2, transforming growth factor beta (TGF-beta)) and intestine tissue was collected for intestine histological analysis. Results: We observed decreased Treg/Th17 ratios in CD4(+) T cells in rats with multiple trauma and a strong inverse correlation with disease activity (intestinal histological scores). Conclusion: We suggest a role for immune imbalance in the pathogenesis and development of multiple trauma. The alteration of the index of Treg/Th17 cells likely indicates the therapeutic response and progress in the clinic. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.