Department of Surgery, University of Virginia Health System, Charlottesville, VA 22908, USA.
J Thorac Cardiovasc Surg. 2010 Feb;139(2):474-82. doi: 10.1016/j.jtcvs.2009.08.033. Epub 2009 Nov 11.
Adenosine A(2A) receptor activation potently attenuates lung ischemia-reperfusion injury. This study tests the hypothesis that adenosine A(2A) receptor activation attenuates ischemia-reperfusion injury by inhibiting CD4+ T cell activation and subsequent neutrophil infiltration.
An in vivo model of lung ischemia-reperfusion injury was used. C57BL/6 mice were assigned to either sham group (left thoracotomy) or 7 study groups that underwent ischemia-reperfusion (1 hour of left hilar occlusion plus 2 hours of reperfusion). ATL313, a selective adenosine A(2A) receptor agonist, was administered 5 minutes before reperfusion with or without antibody depletion of neutrophils or CD4+ T cells. After reperfusion, the following was measured: pulmonary function using an isolated, buffer-perfused lung system, T cell infiltration by immunohistochemistry, myeloperoxidase and proinflammatory cytokine/chemokine levels in bronchoalveolar lavage fluid, lung wet/dry weight, and microvascular permeability.
ATL313 significantly improved pulmonary function and reduced edema and microvascular permeability after ischemia-reperfusion compared with control. Immunohistochemistry and myeloperoxidase content demonstrated significantly reduced infiltration of neutrophils and CD4+ T cells after ischemia-reperfusion in ATL313-treated mice. Although CD4+ T cell-depleted and neutrophil-depleted mice displayed significantly reduced lung injury, no additional protection occurred when ATL313 was administered to these mice. Expression of tumor necrosis factor-alpha, interleukin 17, KC, monocyte chemotactic protein-1, macrophage inflammatory protein-1, and RANTES were significantly reduced in neutrophil- and CD4+ T cell-depleted mice and reduced further by ATL313 only in neutrophil-depleted mice.
These results demonstrate that CD4+ T cells play a key role in mediating lung inflammation after ischemia-reperfusion. ATL313 likely exerts its protective effect largely through activation of adenosine A(2A) receptors on CD4+ T cells and neutrophils.
腺苷 A（2A）受体的激活可有效减轻肺缺血再灌注损伤。本研究旨在验证这样一个假说，即通过抑制 CD4+T 细胞的激活及其随后的中性粒细胞浸润，腺苷 A（2A）受体的激活可减轻缺血再灌注损伤。
采用体内肺缺血再灌注损伤模型。将 C57BL/6 小鼠分为假手术组（开胸）或 7 个研究组，这些研究组经历缺血再灌注（左肺门阻断 1 小时加再灌注 2 小时）。在再灌注前 5 分钟给予 ATL313（一种选择性的腺苷 A（2A）受体激动剂），并与中性粒细胞或 CD4+T 细胞的抗体耗竭联合应用。再灌注后，测量以下指标：使用分离的缓冲液灌流肺系统评估肺功能，免疫组化评估 T 细胞浸润，支气管肺泡灌洗液中的髓过氧化物酶和促炎细胞因子/趋化因子水平，肺湿/干重和微血管通透性。
与对照组相比，ATL313 可显著改善肺功能，减轻缺血再灌注后的水肿和微血管通透性。ATL313 治疗组的缺血再灌注后中性粒细胞和 CD4+T 细胞浸润明显减少。虽然 CD4+T 细胞耗竭和中性粒细胞耗竭小鼠的肺损伤明显减轻，但当将 ATL313 给予这些小鼠时，并未观察到进一步的保护作用。中性粒细胞和 CD4+T 细胞耗竭小鼠的肿瘤坏死因子-α、白细胞介素 17、KC、单核细胞趋化蛋白-1、巨噬细胞炎症蛋白-1 和 RANTES 的表达明显降低，并且仅在中性粒细胞耗竭小鼠中，ATL313 进一步降低了这些趋化因子的表达。
这些结果表明，CD4+T 细胞在介导缺血再灌注后的肺炎症中发挥关键作用。ATL313 可能主要通过激活 CD4+T 细胞和中性粒细胞上的腺苷 A（2A）受体发挥其保护作用。
