Objective To investigate the protection mechanism of long-range hypoxia preconditioning to brain by observing the serum concentration of NO and activity of NOS after repeated upper arm compressions. Methods This study included 8 healthy volunteers who were subjected to repeated upper arm compressions, and their feelings were recorded during compressions. Venous blood samples were collected before and just after repeated compressions, and at 15 min ,30 min ,60 min ,24 h after compressions, another 2 ml venous blood sample was collected for measurement of the concentration of NO and activity of NOS, 1 ml respectively. Results When compression times were increased, the discomfortableness of volunteers decreased ( F = 3.474, P < 0.05 ). The concentration of NO had two peaks, but had no significant difference between them ( F=0.645 ,P >0.05). The activity of NOS was gradually increased after repeated oppressions, and had significant difference (F=18.273, P < 0.01 ). Conclusion Hypoxia preconditioning can induce the tolerance of body to severe ischemia and hypoxia to some extent. After preconditioning, NO and NOS are decreased early, but increased soon later.%目的 观察重复上臂压迫后人血浆中一氧化氮(NO)和一氧化氮合酶(NOS)的表达,探讨远程低氧预适应对脑组织的保护机制.方法 选取8名健康受试者(20～40岁之间,既往健康)随机分两组,空腹进行重复上臂压迫,在此过程中记录受试对象的主观感受.除重复加压前后各采一次远端静脉血外,在重复加压后15、30、60 min和24 h时间点再各采1次血,每次2 ml,用肝素抗凝,离心,分别用NO测定试剂盒(硝酸还原酶法)和NOS测定试剂盒测定NO和NOS.结果 随着重复压迫次数的增加,受试者的主观不适感逐渐下降,差异具有统计学意义(F=3.474,P<0.05),NO含量在实验中形成两个小高峰,各时间点之间差异无统计学意义(F=0.645,P>0.05).而NOS活性在重复压迫后逐渐上升,各时间点所测NOS活性之间差异有统计学意义(F=18.273,P<0.01).结论 低氧预适应可以对机体缺血缺氧产生一定的耐受性,预适应后早期NO含量和NOS活性下降,后期NO和NOS活性增加,通过调节不同种类NOS的活性而对机体)达到保护作用.
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