CD4^+ T淋巴细胞在肺移植缺血再灌注损伤中的作用

Effect of CD4^+ T lymphocyte during ischemia/reperfusion injury in lung transplantation

目的研究CD4+T淋巴细胞在肺移植缺血再灌注损伤中的作用。方法移植成功后的32只大鼠受体随机分为4组,即再灌注观察1 h、1.5 h、2 h和4 h组,另取8只大鼠作为对照组。4组移植之后均给予50%N2+50%O2通气,再灌注后1 h、1.5 h、2 h和4 h分别处死受体,取外周血和移植肺组织,通过酶联免疫方法测量外周血和组织中CD4+T淋巴细胞分泌的因子:IL-2、IL-4、IL-10和IFN-γ的浓度,另外取部分移植肺组织通过免疫组织化学染色观察CD4+T淋巴细胞在移植肺中的浸润情况。结果与对照组比较,再灌注后外周血中IL-2和IFN-γ在1.5 h和2 h时间点升高明显(P<0.05),在4 h点下降(P>0.05);与对照组比较,外周血中IL-4在1 h和1.5 h没有变化,再灌注后2 h和4 h时间点升高(P<0.05);而IL-10在再灌注后1 h和1.5 h升高(P<0.05),2 h和4 h点下降,与基础值比较没有统计学意义(P>0.05)。与对照组比较,再灌注后组织匀浆中IL-2升高(P<0.05),但在再灌注后4 h点有所下降(P<0.05);组织匀浆中IFN-γ在再灌注后1.5 h后升高(P<0.05),在1.5 h时达到高峰(P<0.05),在2 h和4 h点开始下降,与对照组比较有统计学意义(P<0.05);组织匀浆中IL-4在灌注后1 h开始升高(P<0.05),在再灌注后4 h后达到高峰(P<0.05);IL-10在再灌注后1 h达到高峰(P<0.05),然后开始下降,再灌注后4 h与对照组比较没有统计学差异(P>0.05)。免疫组化染色显示,CD4+T淋巴细胞在再灌注后1 h达到高峰,而后逐渐下降(P<0.05),再灌注4 h后,下降至对照组水平(P>0.05)。结论CD4+T淋巴细胞在肺缺血再灌注损伤中不仅仅分泌损伤性因子IL-2和IFN-γ,损伤移植肺组织,还通过Th2细胞分泌的保护性因子IL-4和IL-10对肺缺血再灌注损伤起到一定的抑制作用。

Objective To investigate the effect of CD4^＋T lymphocyte during ischemia/reperfusion（I/R） injury in lung transplantation.Methods Thirty-two Wistar rats were randomized in four groups 1 h,1.5 h,2 h and 4 h after reperfusion,the other 8 Wistar rats were control group.The four groups were ventilated with 50% N2＋50% O2 after lung transplantation.The recipients were sacrificed at four time-point and the blood and graft were preserved to survey the IL-2,IL-4,IL-10 and IFN-γ using the enz-ymelabeled immunosorbent assay.Moreover,the infiltration of CD4^＋T lymphocyte in transplanted lung was surveyed after reperfusion by immunohistochemistry staining.Results Compared with the control group,the IL-2 and IFN-γ in blood were significantly higher at 1.5 h and 2 h after reperfusion（P〈0.05）,and down-regulated at 4 h（P〉0.05）.Compared with control group,there was no significantly change of IL-4 at 1 h and 1.5 h（P〉0.05）,but the IL-4 significantly up-regulated at 2 h and 4 h（P〈0.05）.However,the IL-10 was significantly increased at 1 h and 1.5 h（P〈0.05）,decreased at 2 h and 4 h compared with control group（P〉0.05）.The IL-2 in homogenate was significantly increased compared with control group（P〈0.05）,but decreased at 4 h after reperfusion（P〈0.05）.The IFN-γ in homogenate was significantly increased at 1.5 h（P〈0.05） and up-to the highest level at 1.5 h（P〈0.05） and then decreased but also higher than control group（P〈0.05）.The IL-4 of homogenate was increased from 1 h after reperfusion（P〈0.05） and highest level at 4 h（P〈0.05）.The IL-10 was increased up to the highest level at 1 h（P〈0.05） and decreased during ensuing period,at 4 h after reperfusion there was no significant difference compared with the control group（P〉0.05）.The result of immunohistochemistry showed that CD4^＋T lymphocyte increased significantly at 1 h after reperfusion and decreased during the ensuing time,and down-regulated to control level（P〉0.05）.Conclusion The CD4^＋ T lymphocyte not only may damage the transplanted lung in lung I/R injury by secretion of IL-2 and IFN-γ,but also play a protective effect on the lung I/R injury via the cytokines of IL-4 and IL-10 secreted by Th2 cell.