Ratasirayakorn W, Leone P, Leblebicioglu B, Walters J D
Section of Periodontology, College of Dentistry, The Ohio State University Health Sciences Center, Columbus 43210, USA.
J Periodontol. 1999 Feb;70(2):179-84. doi: 10.1902/jop.1999.70.2.179.
Polymorphonuclear leukocytes (PMNs) are exposed to high concentrations of polyamines in the inflamed periodontium and possess a transport system for taking up these compounds. Previous studies suggest that polyamines are involved in priming of the PMN respiratory burst by tumor necrosis factor-alpha (TNF-alpha) and can stabilize DNA against degradation. The purpose of this study was to determine whether exogenous polyamines can modulate priming by TNF-alpha or delay nuclear changes associated with PMN apoptosis (programmed cell death).
Isolated human PMNs were incubated with putrescine or spermidine in vitro. Superoxide generation was measured with a cytochrome C reduction assay, and apoptotic changes were assessed by fluorescence microscopy (after cell staining with acridine orange and ethidium bromide).
Incubation with 1 mM putrescine for 1 hour inhibited superoxide production by TNF-primed PMNs by 20%, but enhanced the production of superoxide by unprimed cells by 38%. Both effects were dose dependent and statistically significant (P <0.03, repeated measures ANOVA and Dunnett's test). Spermidine had no significant effects on PMN oxidative function. With regard to apoptosis, 1 mM putrescine or spermidine produced a statistically significant reduction in the proportion of apoptotic PMNs within 6 to 9 hours (P <0.05). In cells incubated for 7 hours with 300 microM putrescine or spermidine, the proportion of apoptotic cells was approximately 30% lower than in untreated controls (P <0.05, Dunnett's test). The delay of apoptosis by spermidine was less profound than that produced by TNF-alpha and was not additive to the effects of this cytokine.
Polyamines could potentially impair the priming of PMN oxidative function by TNF-alpha at sites where this cytokine is present. In the absence of TNF-alpha, polyamines could enhance PMN superoxide release and enhance the maintenance of PMN function in the periodontal pocket.
多形核白细胞（PMN）在炎症性牙周组织中会接触到高浓度的多胺，并且拥有摄取这些化合物的转运系统。先前的研究表明，多胺参与肿瘤坏死因子-α（TNF-α）引发的PMN呼吸爆发，并且可以稳定DNA以防止降解。本研究的目的是确定外源性多胺是否可以调节TNF-α引发的反应或延迟与PMN凋亡（程序性细胞死亡）相关的核变化。
将分离出的人PMN在体外与腐胺或亚精胺一起孵育。用细胞色素C还原试验测量超氧化物的产生，并通过荧光显微镜（用吖啶橙和溴化乙锭对细胞染色后）评估凋亡变化。
用1 mM腐胺孵育1小时可使TNF引发的PMN的超氧化物产生抑制20%，但可使未引发的细胞的超氧化物产生增加38%。两种作用均呈剂量依赖性且具有统计学意义（P <0.03，重复测量方差分析和Dunnett检验）。亚精胺对PMN氧化功能无显著影响。关于凋亡，1 mM腐胺或亚精胺在6至9小时内使凋亡PMN的比例产生统计学上的显著降低（P <0.05）。在用300 microM腐胺或亚精胺孵育7小时的细胞中，凋亡细胞的比例比未处理的对照低约30%（P <0.05，Dunnett检验）。亚精胺对凋亡的延迟作用不如TNF-α产生的作用明显，并且与该细胞因子的作用无相加性。
在存在该细胞因子的部位，多胺可能会损害TNF-α对PMN氧化功能的引发作用。在不存在TNF-α的情况下，多胺可增强PMN超氧化物释放并增强牙周袋中PMN功能的维持。
