Tei指数在评价高血压诱导的小鼠左室舒张功能减低中的应用

Assessment of the Left ventricular Diastolic Dysfunction Induced by Hypertension in Mice Using Tei Index

目的探索Tei指数在评价小鼠高血压诱导的心脏纤维化和左室舒张功能减低中的应用。方法 C57BL/6雄性小鼠皮下植入血管紧张素II(Ang II)微渗透泵诱导高血压。在第14天动态监测小鼠清醒血压,行超声心动图检测,采集二尖瓣血流频谱图像及二尖瓣瓣环运动频谱图像,测量并计算等容收缩期时间、等容舒张期时间、射血时间及Tei指数等参数。心脏取材后置于4%多聚甲醛中固定,石蜡包埋,行天狼猩红染色。结果 Ang II组小鼠在第14天收缩压显著增高(159±5.6 mm Hg vs 108±2.1 mm Hg,P<0.001),心脏间质出现明显胶原沉积。超声心动图提示Ang II组小鼠Tei指数与Vehicle组相比显著增高(0.93±0.07 vs 0.57±0.04,P<0.001)。此外,无论给予1%或3%异氟烷麻醉,两种不同麻醉深度和心率水平下Ang II组小鼠的Tei指数均显著高于Vehicle组。结论 Tei指数能够准确、灵敏且稳定地反映高血压状态下小鼠心脏左室舒张功能降低,且该参数几乎不受小鼠麻醉深度和心率的影响。

Objective To explore the availability of Tei index on assessment of the left ventricular diastolic dysfunction induced by hypertension in mice. Methods Male C57 BL/6 mice were subcutaneously implanted with an osmotic pump which released angiotensin II（Ang II）. Blood pressure were monitored and echocardiography were performed on day 14. Mitral valve f low spectrum and mitral valve ring motion spectr um were obtained, then isovolumic relaxation time（IVRT）, isovolumic contraction time（IVCT）, ejection time（ET） and Tei index were measured and calculated. Hear ts were f ixed with 4% parafor maldehyde and embedded in paraff in, sections were stained with eosin and Picrosirius red. Results Inf usion of Ang II signif icantly increased systolic blood pressure compared to saline infused mice 2 weeks after infusion pump implantation（159±5.6 mm Hg vs 108±2.1 mm Hg, P〈0.001）. And heart of Ang II group exhibited marked collagen deposition. Tei index acquired by echocardiography were significantly increased compared with vehicle group（0.93±0.07 vs 0.57±0.04, P〈0.001）. Furthermore, the two groups differed in Tei index regardless of 1% or 3% isoflurane concentration used for anesthesia. Conclusion Tei index provides a precise and sensitive method for evaluation of left ventricular diastolic dysfunction induced by hypertension in mice. More importantly, this parameter is hardly affected by anesthesia depth and heart rate of mice.