猕猴肠缺血再灌注激活了补体旁路途径

The pathway of complement activation in intestinal ischemia reperfusion in macaque

补体激活是炎症反应放大的重要环节之一。本文通过猕猴肠缺血再灌注(IIR)的实验,探讨由此发展的多器官功能障碍综合征(MODS)究竟是通过何种途径激活补体?以增加对全身炎症反应内源性保护机制的认识。通过肠系膜上动脉夹闭—松解术分别造成5只猕猴肠缺血再灌注损伤,采用免疫速率散射比浊法、CH50总补体测定法测定血C3、C4、C-反应蛋白(CRP)、总补体的变化,免疫细胞化学观察中性粒细胞(PMN)上IL-1、NF-κB变化,流式细胞仪测定PMN凋亡率。IIR后24 h,体内总补体由(106.6±18.07)U/ml降至(62.1±9.52)U/ml,P>0.05;其中,C3下降了30%,P>0.05;C4在IIR前后无明显变化(0.1342±0.07 vs 0.1420±0.06,P>0.05)。PMN的凋亡率由IIR前的15.4%±1.41%显著降低至IIR后3.5%±0.53%,P>0.05,其IL-1、NF-κB表达增加;CRP由IIR前的(4.33±1.31)mg/L增加至IIR后的(17.73±0.86)mg/L,P>0.01。IIR后补体通过旁路途径激活,活化补体片段抑制PMN凋亡,增加急性时相炎症蛋白如CRP、IL-1的表达,使炎症放大至全身,推动了MODS的发生。

The role of pathway of complement activation in intestinal ischemia reperfusion （IIR） in macaque was investigated in the present study by observing the changes in complement and C-reactive protein （CRP） in macques with multiple organ dysfunction syndrome （MODS）. This macaque model was established by clamping superior mesenteric artery to produce the intestinal ischemia reperfusion damage. In these model of macaque the levels of total complement, complement components and CRP were determined with rate scattering turbidometer （Beckman Coulter） immunocytochemical assays were used to determine the changes in IL-1 and NF-κB on polymorphonuclear leukocytes （PMN）, and the apoptotic rate of PMN was determined by flow cytometery. It was demonstrated that the level of the total complement content was significantly decreased from （106 ± 18. 07） U/ml to （62.1 ± 9.52） U/ml 24 hours after IIR injury （P〈0.05） ; the decreased level of C3 accounted to 30%, however, level of C4 showed no significant changes before or after IIR（0. 1342±0.07 vs 0. 1420±0.06, P〉0.05）, level of CRP increased from （4.33±1.31） mg/L before IR to （17.73±0.86） mg/L after IR. The apoptotic rate of PMN decreased from 15.4 % ± 1.41% before IR to 3.5 % ± 0.53 % （P〈0.05） after IIR, and the expressions of IL-1 and NF-κB in PMN increased significantly. From the above observatons, it fs apparent that after intestinal ischemia reperfusion, complements were activated through the alternate pathway of complement activation, and the activated complement fragments can inhibit apoptosis of PMN and promote the expressions of acute phase inflammatory proteins, such as CRP and IL-1, thus amplifying the inflammatory reactions to the whole body and inducing the development of multiple organ dysfunction syndrome.