生长抑素对猕猴肠缺血再灌注损伤作用研究

Associative investigation of somatostatin levels and PMN life in intestinal ischemia reperfusion in macaque

[目的]探讨多器官功能障碍综合征(MODS)时体内中性粒细胞(PMN)凋亡延迟的潜在原因,以增加对全身炎症反应内源性保护机制的认识。[方法]将15只猕猴分为正常对照组、肠缺血再灌注(IIR)组、IIR+生长抑素(SST)组,每组5只。用放射免疫分析法测定各组外周血、肠黏膜SST浓度,SST与猕猴外周血PMN共同孵育后,观察猕猴外周血PMN的形态变化,流式细胞仪测定细胞凋亡率,电泳分析PMN细胞DNA断裂片段,生物分子相互作用系统检测PMN上SST受体(SSTR-1,SSTR-2)。[结果]IIR后,猕猴外周血及小肠黏膜中SST含量均明显下降;IIR组IIR 24h后PMN凋亡率降至(3.5±0.5)%,与IIR+SST组[(7.5±1.4)%]、正常对照组[(15.4±1.4)%]比较均差异有统计学意义(P<0.05);腹腔巨噬细胞凋亡率则明显增加,与IIR+SST组、正常对照组比较[(20.2±1.8)%∶(17.5±1.2)%、(14.1±1.6)%]均差异有统计学意义(P<0.05);SSTR在IR时表达下降,静脉滴注SST后随着全身状况的好转,SSTR表达增加。[结论]生理状态下,SST通过猕猴外周血PMN上SSTR介导,诱导其凋亡;IIR后猕猴外周血及小肠黏膜中SST含量明显下降,这使得PMN寿命延长,从而推动了全身炎症反应综合征和MODS的发生。

[Objective]Previous studies have shown that delayed apoptotic polymorphonuclear neutrophils（PMNs）might play an important role in the development of multiple organ dysfunction syndromes （MODS）.This study was to investigate the relationship between somatostatin（SST） levels in plasma or jejunum tissue and PMN life in macaques following intestinal ischemia reperfusion.[Methods]MODS model in macaque was established by clamping superior mesenteric artery.The levels of SST in plasma and jejunum tissue were measured by radioimmunoassay.After incubated with SST,the apoptotic PMN were determined by the morphological studies,flow cytometer and DNA agarose electrophoresis.The expression of SSTR on PMN was detected by biosensor.[Results] The apoptotic rate of PMNs was obviously reduced （[15.4＆#177;1.41]% to [3.5＆#177;0.53]%,P〈0.05）.Specific DNA ladder bends from PMNs were visualized with agarose electrophoresis.Specific bindings between PMNs and the antibodies for SSTR1 （[547.9＆#177;19.98] RU/ml） or SSTR2 （[27.6＆#177;20.56] RU/ml） were detected.[Conclusion]The results showed physiological apoptosis of PMNs in macaques could be induced by SST through SSTRs on PMNs.The decreased SST levels in macaque plasma or jejunum tissue following intestinal ischemia-reperfusion might extend PMN life and promote the occurrence of MODS.