心肌梗死对C57BL/6J小鼠跑轮运动日节律的影响

Influence of Myocardial Infarction on the Circadian Rhythm of Locomotor Activities in C57BL /6J Mouse

目的心脏活动的昼夜变化受生物钟中枢视交叉上核(SCN)调控,因而反映心脏活动的生理指标(如血压、心率、心排出量)乃至心源性猝死事件呈现明显的昼夜节律。反过来,心脏疾病也可能影响SCN的昼夜节律振荡。本研究旨在探讨心肌梗死对SCN日节律的影响。方法通过经腹腔横膈膜液氮冷冻致局部心肌坏死的方法模拟小鼠心肌梗死,利用Mini Mitter跑轮活动监测系统实时监测C57BL/6J小鼠心肌梗死前后跑轮运动节律的改变。结果心肌梗死后小鼠的运动周期由23.76±0.27h缩短到23.21±0.15h,但运动活性改变不明显。结论心肌梗死使C57BL/6J小鼠的跑轮运动日节律周期缩短,推测心肌梗死可能重调中枢SCN的周期振荡。

Objective The circadian variation of cardiac activity is controlled by the suprachiasmatic nucleus （SCN） , and thus pa- rameters reflecting cardiac activities （such as blood pressure, heart rate, cardiac output） and even cardiac events show obvious circadian oscillations. On the other hand, cardiac diseases may also affect the circadian rhythm. This study aimed to test the hypothesis that myocar- dial infarction （MI） affects the SCN - controlled circadian locomotor activities. Methods Myocardial necrotic injury was created by focal cold shock with liquid nitrogen across the intact diaphragm to mimic MI in C57BL/6J mice. Circadian wheel - running activities were con- tinuously monitored by the Vitalview data acquisition system before and after MI. Results MI shortened the period length of circadian lo- comotor activities （ before MI 23.76 ± 0.27h ; after MI 23.21 ± 0.15h ,P 〈 0.05 ）. However, the activity intensities were not significantly affected by MI. Conclusion MI shortens the period length of the circadian rhythm, but did not significantly affect the activity intensity, in C57BL/6J mice. The study suggests that MI affects the circadian oscillation of the central clock SCN.