Fanning N F, Porter J, Shorten G D, Kirwan W O, Bouchier-Hayes D, Cotter T G, Redmond H P
Department of Surgery, National University of Ireland, Cork, Ireland.
Surgery. 1999 Sep;126(3):527-34.
Neutrophils play a crucial role in host defense against infections, but their inappropriate infiltration and activation within tissues can cause host tissue damage through release of reactive oxygen metabolites, metalloproteinases, and proinflammatory cytokines. The termination of a neutrophil-mediated inflammatory response is effected through programmed cell death or apoptosis. Delayed neutrophil apoptosis is associated with proinflammatory diseases, such as the systemic inflammatory response syndrome. Surgery induces a profound inflammatory response; therefore, neutrophil apoptosis of patients undergoing elective surgery was investigated.
Nonseptic patients undergoing elective orthopedic surgery while under epidural anesthesia had neutrophils and platelet-poor isolated from whole venous blood harvested at 4 time points: pre-epidural, 45 minutes postepidural but before surgical intervention, 1 hour postsurgical incision, and 24 hours postsurgery. Neutrophil apoptosis was quantified at 1, 12, and 24 hours in culture by immunofluorescence flow cytometry of annexin V and propidium iodide staining and confirmed by TUNEL (terminal deoxynucleotidyl transferase nick end labeling) assay for DNA strand breaks. Serum cytokines were quantified by specific enzyme-linked immunosorbent assay.
Spontaneous neutrophil apoptosis after elective surgery was significantly (P < .001) inhibited with an effect evident within an hour of surgical incision and persisting at 24 hours postsurgery. The addition of patients' 24 hour postoperative plasma to healthy neutrophils markedly (P < .01) reduced neutrophil apoptosis, whereas plasma taken an hour after surgical incision was ineffective. Interleukin (IL)-6 was notably increased (1395 +/- 196 pg/mL, P < .01) 24 hours postsurgery and at this postoperative concentration inhibited (P < .01) apoptosis of normal neutrophils. Levels of other inflammatory mediators (IL-1 beta, tumor necrosis factor alpha, granulocyte-macrophage colony-stimulating factor, soluble Fas, soluble Fas ligand) were unaltered. The anti-inflammatory cytokine IL-10 was only slightly increased 24 hours postsurgery (8.32 +/- 2.99 pg/mL); however, the addition of recombinant human IL-10 (10 ng/mL) counteracted (P < .05) inhibition of neutrophil apoptosis induced by IL-6 and post-surgery plasma.
These results identify marked inhibition of neutrophil apoptosis after elective surgery and suggest that the inhibition of neutrophil apoptosis in the postoperative period is, at least in part, a result of soluble circulating factors. The marked imbalance favoring proinflammatory over anti-inflammatory cytokine release in the immediate postoperative period mediates the overwhelmingly antiapoptotic net capacity of postsurgery plasma.
中性粒细胞在宿主抵御感染的防御中发挥关键作用，但它们在组织内的不适当浸润和激活可通过释放活性氧代谢产物、金属蛋白酶和促炎细胞因子导致宿主组织损伤。中性粒细胞介导的炎症反应通过程序性细胞死亡或凋亡而终止。中性粒细胞凋亡延迟与促炎疾病相关，如全身炎症反应综合征。手术可引发强烈的炎症反应；因此，对接受择期手术患者的中性粒细胞凋亡进行了研究。
在硬膜外麻醉下接受择期骨科手术的非脓毒症患者，在4个时间点采集全静脉血，分离出中性粒细胞和血小板：硬膜外麻醉前、硬膜外麻醉后45分钟但在手术干预前、手术切口后1小时和术后24小时。通过膜联蛋白V和碘化丙啶染色的免疫荧光流式细胞术在培养1、12和24小时时对中性粒细胞凋亡进行定量，并通过TUNEL（末端脱氧核苷酸转移酶缺口末端标记）测定法确认DNA链断裂。通过特异性酶联免疫吸附测定法对血清细胞因子进行定量。
择期手术后中性粒细胞的自发凋亡受到显著抑制（P <.001），手术切口后1小时内即可观察到这种效应，并持续至术后24小时。将患者术后24小时的血浆加入健康中性粒细胞中可显著（P <.01）降低中性粒细胞凋亡，而手术切口后1小时采集的血浆则无效。术后24小时白细胞介素（IL）-6显著升高（1395±196 pg/mL，P <.01），在此术后浓度下可抑制（P <.01）正常中性粒细胞的凋亡。其他炎症介质（IL-1β、肿瘤坏死因子α、粒细胞-巨噬细胞集落刺激因子、可溶性Fas、可溶性Fas配体）的水平未改变。抗炎细胞因子IL-10在术后24小时仅略有升高（8.32±2.99 pg/mL）；然而，加入重组人IL-10（10 ng/mL）可抵消（P <.05）IL-6和术后血浆诱导的中性粒细胞凋亡抑制作用。
这些结果表明择期手术后中性粒细胞凋亡受到显著抑制，并提示术后中性粒细胞凋亡的抑制至少部分是可溶性循环因子作用的结果。术后即刻促炎细胞因子释放相对于抗炎细胞因子释放的显著失衡介导了术后血浆压倒性的抗凋亡净能力。
