Vazan R, Janega P, Hojná S, Zicha J, Simko F, Pechánová O, Styk J, Paulis L
Institute of Pathophysiology, Comenius University, Bratislava, Slovak Republic.
Physiol Res. 2007;56 Suppl 2:S63-S69. doi: 10.33549/physiolres.931399. Epub 2007 Sep 5.
Factors modulating cardiac susceptibility to ischemia-reperfusion (I/R) are permanently attracting the attention of experimental cardiology research. We investigated, whether continuous 24 h/day light exposure of rats can modify cardiac response to I/R, NO-synthase (NOS) activity and the level of oxidative load represented by conjugated dienes (CD) concentration. Two groups of male adult Wistar rats were studied: controls exposed to normal light/dark cycle (12 h/day light, 12 h/day dark) and rats exposed to continuous light for 4 weeks. Perfused isolated hearts (Langendorff technique) were exposed to 25 min global ischemia and subsequent 30 min reperfusion. The recovery of functional parameters (coronary flow, left ventricular developed pressure, contractility and relaxation index) during reperfusion as well as the incidence, severity and duration of arrhythmias during first 10 min of reperfusion were determined. The hearts from rats exposed to continuous light showed more rapid recovery of functional parameters but higher incidence, duration and severity of reperfusion arrhythmias compared to controls. In the left ventricle, the NOS activity was attenuated, but the CD concentration was not significantly changed. We conclude that the exposure of rats to continuous light modified cardiac response to I/R. This effect could be at least partially mediated by attenuated NO production.
调节心脏对缺血再灌注（I/R）易感性的因素一直吸引着实验心脏病学研究的关注。我们研究了大鼠每天持续24小时光照是否会改变心脏对I/R的反应、一氧化氮合酶（NOS）活性以及以共轭二烯（CD）浓度表示的氧化负荷水平。研究了两组雄性成年Wistar大鼠：一组为暴露于正常光照/黑暗周期（每天12小时光照，12小时黑暗）的对照组，另一组为连续光照4周的大鼠。采用Langendorff技术对离体灌注心脏进行25分钟全心缺血及随后30分钟再灌注处理。测定再灌注期间功能参数（冠状动脉血流量、左心室舒张末压、收缩性和舒张指数）的恢复情况以及再灌注最初10分钟内心律失常的发生率、严重程度和持续时间。与对照组相比，连续光照大鼠的心脏功能参数恢复更快，但再灌注心律失常的发生率、持续时间和严重程度更高。左心室内，NOS活性减弱，但CD浓度无显著变化。我们得出结论，大鼠持续光照会改变心脏对I/R的反应。这种效应可能至少部分由一氧化氮生成减弱介导。
