Role of polymorphonuclear neutrophil (PMN) cell death in inflammation and infection

本研究探讨了多形核中性粒细胞（PMN）死亡在炎症和感染中的作用，获得了以下结果：（1）健康志愿者的PMN与大肠杆菌（E.coli）以不同比例共培养。然后通过流式细胞术分析PMN的细胞死亡、活性氧中间体（ROI）产生和CD 16表达。还评估了形态学特征。DNA凝胶电泳证实PMN凋亡。还测量了无细胞上清液中的TNF-α、IL-1 β和IL-6水平。低剂量大肠杆菌可抑制PMN凋亡。相反，高剂量的大肠杆菌增加了PMN的坏死。与大肠杆菌共培养后，PMN凋亡的平均百分比与无细胞上清液中的细胞因子水平呈显著负相关。与大肠杆菌共培养后ROI产量增加，而与大肠杆菌共培养后CD 16表达下降。(2)PMN与各种细胞因子包括TNF-α、IL-1 关于我们 β、IL-6、IL-8、GM-CSF和IL-10。然后，评估PMN细胞死亡。低剂量TNF-α抑制PMN凋亡，高剂量TNF-α促进PMN凋亡。IL-1 β、IL-6和GM-CSF可抑制PMN凋亡。IL-10减弱IL-6对PMN凋亡的抑制作用。(3)用GH（0或100 ng/mL）预处理PMN 3 h，然后培养0、4或12 h，通过流式细胞术分析PMN的细胞死亡、ROI产生、CD 16和Fas表达。GH在培养12小时时抑制PMN凋亡。GH促进PMNs产生ROI，GH降低PMNs表面Fas表达。(4)在手术前、手术后第1天、第3天和第7天从患者采集外周血样品。在手术后第1、2和3天通过腹腔引流无菌获得腹膜样品。通过流式细胞术分析PMN的细胞死亡。术后第1、3天外周血中性粒细胞凋亡受到抑制，第7天凋亡增加。术后第1天腹腔PMN凋亡也受到抑制，第3天凋亡明显增加。这些结果表明，通过抑制PMN细胞死亡，增强PMN的杀菌功能，可能有利于宿主抵抗细菌感染和/或脓毒症。少

We investigated the role of polymorphonuclear neutrophil(PMN)cell death in inflammation and infection, and obtained the following findings :(1) PMNs from healthy volunteers were cocultured with or without live E.coli at different ratios. The PMNs were then analyzed by flow cytometry for cell death, reactive oxygen intermediates (ROI) production, and CD16 expression. Morphologic features also were assessed. PMN apoptosis was confirmed by DNA gel electrophoresis. TNF-alpha, IL-1beta and IL-6 levels in cell free supernatants were also measured. Low doses of E.coli inhibited PMN apoptosis. In contrast, a high dose of E.coli increased PMN necrosis. The mean percentages of PMN apoptosis after coculture with E.coli showed significant inverse correlations with cytokine levels in cell free supernatants. While ROI production increased after coculture with E.coli, CD16 expression decreased after coculture with E.coli.(2) PMNs were cultured with various kinds of cytokines including TNF-alpha, IL-1 … More beta, IL-6, IL-8, GM-CSF and IL-10. Then, PMN cell death was assessed. While low dose of TNF-alpha inibited PMN apoptosis, high dose of TNF-alpha increased PMN apoptosis. IL-1beta, IL-6 and GM-CSF inhibited PMN apoptosis. IL-10 attenuated PMN apoptosis inhibition by IL-6.(3) PMNs were pretreated with GH (0 or 100 ng/mL) for 3 hours, then cultured for 0, 4 or 12 hours and PMNs were analyzed by flow cytometry for cell death, ROI production, CD16 and Fas expression. GH inhibited PMN apoptosis at 12 hours of culture. GH enhanced ROI production by PMNs, and GH decreased Fas expression on PMNs.(4) Peripheral blood samples were collected from patient before surgery, on day 1, 3, and 7 after surgery. Peritoneal samples were obtained aseptically through abdominal drain on day 1, 2 and 3 after surgery. PMNs were analyzed by flow cytometry for cell death. Peripheral PMN apoptosis was inhibited on day 1 and 3, and increased on day 7 after surgery. Peritoneal PMN apoptosis also was inhibited on day 1 after surgery, and significantly increased by days 3.These findings suggest that augmented PMN bactericidal function, via inhibition of PMN cell death, may be beneficial for host defense against bacterial infection and/or sepsis. Less