比较麻醉和清醒状态对高频超声心动图评价小鼠心功能影响的研究

目的 比较小鼠在麻醉和清醒状态下，高频超声心动图检测心功能的重复性和可行性。方法 随机将40只小鼠平均分为两组，在清醒的基础状态下予超声心动图检查一次，随后麻醉组腹腔注射氯胺酮和甲苯噻嗪，清醒组注射同等剂量生理盐水，每隔10min检测超声心动图一次，至30min后变为隔15min一次，至第60min停止。观察心率、左室短轴缩短率（FS）、每分钟心输出量（CO）随时间的变化情况。结果 与基础状态比较，麻醉剂使小鼠心率、FS、CO显著降低（P〈0．05），在10～20min降为最低，随后逐渐恢复，至第60min不能完全恢复至基础状态；左室收缩末期内径（LVESD）和舒张末期内径（LVEDD）均扩大，第20min最大，随后降低，LVEDD能在第60min恢复至基础值，而LVESD不能恢复正常；小鼠的心率与FS呈正相关（r=0．884，P〈0．001）。清醒组小鼠各个时间点测量值变异系数比麻醉组小。结论 麻醉小鼠心功能显著降低，重复测量不稳定；清醒状态下小鼠心功能重复测量稳定。高频超声检查小鼠心脏功能应当采取清醒状态下的评价参数。

Different impact on echocardiography in assessment of cardiac function of mouse under anesthetic or unanesthetic condition

Objective To compare echocardiographic parameters of left ventricular function in mice under anaesthesia with those in conscious condition.Methods Forty mice were randomized to anesthetic group and nonanesthetic group,all mice were examined in conscious state at baseline,then anesthetic group had intraperitoneal injection of ketamine and xylazine,the non-anesthetic group received intraperitoneal injection of the same volume of saline.Echocardiography was performed every 10min and every 15min after 30min time point until 60min.ResultsAnesthetic agent strikingly brought down heart function of mice.The nadir of heart rate,fractional shortening(FS),cardiac output(CO) occurred during 10-20min period and could not be restored to normal value at baseline even after 60min.Left ventricular end-diastolic diameter(LVEDD) and left ventricular end-systolic diameter(LVESD) increased to maximum at 20min point,then decreased to value at baseline until 60min.LVEDD could be restored to baseline value while LVESD remained larger than baseline at 60min.Coefficient of variation of echocardiographic measurement in non-anesthetic group was smaller than those in anethetic group.FS and heart rate of all mice were highly corrrelated by regression analysis(r=(0.884),P<(0.001)).Conclusions Echocardiographic measurement of mouse under conscious condition is a more reliable and reproducible method for evaluating heart function of mouse than those under unconscious condition.