摘要
目的观察自发性高血压大鼠（SHR）左心室心肌力学特征与心内、外膜下胶原分布特点的关系。方法12周龄SHR随机分笼饲养,相隔4～12周进行实验,设部分同周龄段WKY大鼠为对照。观察左心室超声心动图、心导管及心肌组织学指标。二维应变（2DSE）技术分析左心室中段心肌收缩期纵向应变（SL）、周向应变（SC）及径向应变（SR）,心导管检查记录左心室舒张末期压力（LVEDP）和左心室内压最大上升和下降速率（±dp/dtmax）,组织学观察细胞大小、血管周围胶原面积（PVCA）、心内膜下和心外膜下层心肌胶原容积分数（CVF）。结果 45～66周龄SHR纵向应变较28～36周龄降低（-11.58±0.93比-14.72±2.75,P〈0.01）,75～84周龄进一步降低（-8.36±2.16,P〈0.01）,而周向应变、径向应变及左心室射血分数（LVEF）值在75～84周龄才出现降低[75～84周龄与45～66周龄比较,周向应变：-10.23±2.44比-15.34±1.59,径向应变：26.12±7.28比48.80±7.05,LVEF：（67.68±5.40）%比（81.05±3.05）%;均P〈0.01]。心肌CVF与PVCA随周龄增加而增加,45～66周龄心内膜下CVF较28～36周龄增加[（11.79±8.69）%比（4.07±2.89）%,P〈0.05],且45～66周龄时心内膜下CVF显著多于心外膜下[（11.79±8.69）%比（3.68±1.42）%;P〈0.05];纵向应变与心内膜下CVF呈负相关（r=-0.47,P〈0.01）。45周龄时LVEDP较28周龄升高,75周龄后更高。结论 SHR左心室心肌纤维化的发生特点与其心室多维形变障碍的发生、发展是一致的,纵向应变先受损,当周向与径向应变均降低时便出现LVEF下降。
Objective To observe the distribution of myocardial collagen and its relationship with the multi-dimen- sional deformation of left ventricular in spontaneously hypertensive rats （SHR）. Methods Twelve-week-old SHR were examined with an interval of 4 to 12 weeks, and WKY rats at the similar weeks of age were chosen as controls. Conventional parameters and 2DSE measurements including left ventricular longitudinal, radial and circumferential strain （SL, SR, SC） were acquired by echocardiography, and invasive left ventricular end diastolic pressure （LVEDP） and 4-dp/dtmax were detected within 24 hours after echo exam, and collagen volume fraction （CVF） in su bendocardia[ and subepicardial myocardium was observed histologically. Results SL declined at 45 -- 66 weeks compared with 28--36 weeks （--11.58±0.93 vs --14. 724±2.75, P〈0.05） ,and further declined at 75--84 weeks （ --8.36±2. 16,P〈0. 01） ;while SC, SR and LVEF decreased at 75--84 weeks compared with 45--66 weeks ESC： --10.23-＋2.44 vs --15. 34 ±1. 59 ; SR： 26.12±7.28 vs 48.80±7.05; LVEF： （ 67. 68 ± 5. 40 ） % vs （81.05± 3.05）%, all P〈0.05]. CVF in SHR increased with age, remarkably at 45--66 weeks compared with 28--36 weeks ECVF： （11.79±8.69） % vs （4. 07±2.89） %, P〈0. 05]. CVF was significantly higher in subendocardial than in suhepicardial myocardium at 45-- 66 weeks [- （ 11.79 ± 8.69 ） % vs （ 3.68 ± 1.42 ） %, P〈0. 05]. Subendo cardial CVF was correlated negatively with SL （r：--0. 47, P〈0. 01）. LVEDP increased after 45 weeks. Conclusion In SHR, the interstitial collagen developing from inner to outer layer of myocardium was consistent with the impair- ment of myocardial mutidirectional deformation, that is, the damage of SL followed by LVEF decline when all direc-tions of systolic strain reduced.
出处
《中华高血压杂志》
CAS
CSCD
北大核心
2015年第8期736-742,共7页
Chinese Journal of Hypertension
基金
国家自然科学基金项目(81171360)
关键词
高血压
大鼠
应变
心肌纤维化
心功能
Hypertension
Rat
Strain
Myocardial fibrosis
Cardiac function
