Characteristice and significance of change in Treg/Th17 balance in rats with combined trauma and γ-radiation / 解放军医学杂志

ABSTRACT

Objectiv To observe the process of wound healing and investigate the characteristics of Treg/Th17 balance in rats with combined wound and 5 Gy whole-body γ -radiation (CWR) for exploring the interrelationship between wound healing and the immune balance of Treg/Th17. Methods Sixty-five female Wistar rats (clean grade) were randomly divided, depending on weight, into normal control group (normal), wound only group (MW) and wound plus 5 Gy whole body γ -radiation group (RW). The wound area was measured with image analyzer, the peripheral white blood cells (WBC) and lymphocytes (LYM) were counted with automatic cytometry, and the percentage of splenic regulatory T cells (Tregs) and Th17 cells was analyzed by flow cytometry at different time points post CWR. Results (1) The residual wound area was much greater in RW group than in MW group (P<0.01) 7d to 21d after CTR, the wound surface in MW group almost healed on 21d, while that in RW group healed on 28d post CTR. (2) The peripheral WBC and LYM counts were significantly lower in MW group than in normal group (P<0.05) 1d to 7d after CWR, and in RW group than in normal and MW group 1d to 14d after CWR. Furthermore, the WBC count was still obviously lower in RW group than in MW and normal groups 21d to 28 d after CWR. (3) The percentage of splenic Tregs was significantly higher in RW group than that in normal and MW groups (P<0.01) at 3d and 7d after CWR, and returned to normal level at 28 d after CWR. (4) The percentage of Th17 cells was notably higher in RW group than in normal and MW groups (P<0.01) on the first day, reached the peak value on 3 d, and returned to normal level on 28 d after CWR. (5) The ratio of Treg/Th17 was distinctly lower in RW group than in normal and MW groups from 1d to 21d, and approximated normal level on 28d after CWR, indicating that 5Gy whole-body γ-radiation could induce Treg/Th17 imbalance in wounded rats. Conclusions 5 Gy whole-body γ-radiation may delay the process of wound healing in rats. Radiation-induced changes in Tregs and Th17 may lead to the disequilibrium of Treg/Th17, which may be an important factor for delayed wound healing in CWR.