甲酰三肽诱导的环三磷酸腺苷水平升高对其激发中性粒细胞脱颗粒的抑制作用

Inhibitive effect of increased cAMP level induced by fMLP on neureophil degranulation stimulated by fMLP itself

目的 探讨甲酰三肽（N-formyl-methionyl-leucyl-phenylalanine,fMLP）刺激人外周血中性粒细胞（neutrophil,又称多形核白细胞,polymorphonuclear leukocyte,PMN）脱颗粒过程中环三磷酸腺苷（adenosine-3＇,5＇-cyclic monophosphate,cAMP）的变化及其对细胞脱颗粒的影响.方法 采用Percoll不连续梯度密度离心法分离纯化人外周血PMN;以fMLP为刺激物激发PMN脱颗粒,采用放免法检测细胞内cAMP,用酶反应比色法和间接ELISA法检测颗粒标志物髓过氧化物酶（myeloperoxidase,MPO）和乳铁蛋白（lactoferrin,LF）.结果 fMLP刺激1、5 min后PMN胞内cAMP含量显著升高,用cAMP依赖的蛋白激酶A（protein kinase A,PKA）抑制剂h89预处理15 min后,fMLP刺激PMN脱颗粒的作用显著增强.结论 fMLP刺激后使PMN胞内cAMP水平升高,抑制了fMLP本身引起的细胞脱颗粒.

Objective To investigate effects of adenosine-3＂,5＂-cyclic monophosphate （cAMP） on the degranulation of neutrophil stimulated by N-formyl-methionyl-leucyl-phenylalanine （fMLP）. Methods Human neutrophil or polymorphonuclear leukocyte （PMN） isolation was performed by using the discontinuous saline- Percoll gradient technique. PMN degranulation was stimulated by fMLP and cAMP assayed by means of radioimmunoassay, myeloperoxidase （MPO） and lactoferrin （LF） were assayed by enzymology and indirect ELISA respectively. Results cAMP levels increased obviously following stimulation with fMLP for 1 and 5 minutes. The degranulation of neutrophil stimulated by fMLP was strengthened after pretreatment with cAMP- dependent PKA inhibitor h89 for 15 minutes. Conclusions The levels of cAMP increased obviously following stimulation with fMLP and neutrophil degranulation could be inhibited by fMLP itself.