模拟失重对大鼠心肌氧化应激水平的影响

The effect of simulated weightlessness on myocardial oxidative stress in rats

目的观察模拟失重大鼠心肌组织氧化应激水平变化,探讨模拟失重状态下心肌收缩功能下降的可能原因。方法将20只SD大鼠随机分为对照组、模拟失重组,采用尾部悬吊法制作模拟失重模型。3周后所有大鼠断颈处死,取心肌组织测量一氧化氮(NO)、硝基酪氨酸、总抗氧化能力(T-AOC)、诱导型一氧化氮合酶(iNOS)含量;取血清测量iNOS活力。结果模拟失重可显著增加心肌组织NO、硝基酪氨酸含量及iNOS活力,分别为6.23±0.17U/mgprot、0.021±0.007nmol/L和0.150±0.020U/mgprot,而T-AOC则明显下降,为9.161±4.876U/mgprot;对照组分别为4.25±0.21U/mgprot、0.015±0.004nmol/L、0.073±0.020U/mgprot、19.112±12.816U/mgprot,差异有统计学意义(P<0.01,P<0.05)。血清iNOS活力呈增加趋势(P>0.05)。结论 3周模拟失重可增加大鼠的氧化应激水平,使抗氧化能力下降,可能是模拟失重状态下影响心肌收缩功能机制的重要环节之一。

Objective To investigate the effects of simulated weightlessness on myocardial oxidative stress in rats. Methods Twenty rats were randomly divided into two groups equally,control group and tail-suspended group. The former was fed as normal. The latter was tail-suspended. At the end of third week,rat myocardial tissues and serum of two groups were taken simultaneously. The oxidative stress of myocardial tissue were assessed by the levels of NO,nitrotyrosine,total antioxidant capacity（TAOC）and the activity of iNOS. Results The level of NO,nitrotyrosine and the activity of iNOS were 6.23±0.17 U/mgprot,0.021± 0.007 nmol/L and 0.150±0.02 U/mg respectively,increased significantly compared with control group（P0.01 and P0.05= respectively. T-AOC decreased significantly（P0.05）. The activity of iNOS in serum showed an increasing tendency（P0.05）. Conclusions The level of myocardial oxidative stress was increased in simulated weightlessness,which may be the cytological basis for decreased myocardial contractile function under the condition of simulated weightlessness.