摘要
目的:探讨藏羚羊适应高原低氧环境的左心功能特点。方法:捕捉海拔4 300 m藏羚羊9只、藏系绵羊10只运至格尔木(海拔2 800 m)实验基地。测定二者的心脏/体重比(HW/BW)、右心室/(左心室+室间隔)重量比[RV/(LV+IVS)];应用心导管技术测定心率(HR)、收缩压(SBP)、舒张压(DBP)、左室等容收缩期心室内压力上升最大速率和左室等容舒张期心室内压力下降最大速率(±dp/dt)。以格尔木市的氧浓度(21.1%)为基线,分别给予更低浓度氧14.6%、12.5%(分别相当于海拔5 300 m、6 300 m)的低氧吸入15 min后重复测定以上指标。应用透射电镜观察心肌超微结构。结果:藏羚羊HW/BW显著高于藏系绵羊(P<0.01),基础状态下藏羚羊SBP低于藏系绵羊(P<0.05),+dp/dt与藏系绵羊比无显著差异,吸入14.6%和12.5%的低氧气体后藏羚羊+dp/dt分别升高至145.1%和148.1%,而藏系绵羊分别降低至68.4%和70.5%(P<0.05);电镜下观察藏羚羊心肌超微结构与藏系绵羊比较,其心肌细胞线粒体较为丰富。结论:藏羚羊心脏对高海拔低氧环境的适应,是通过增加心脏器官的重量及心肌细胞线粒体的含量来实现,其心肌收缩功能的适应性特征为:在静息状态下以较低的左心室心肌收缩力来降低氧耗量以此适应高原低氧环境,而以海拔更高的较低氧浓度为应激条件下,左心室心肌收缩力明显升高。提示:藏羚羊作为高原适应性动物,经过漫长的自然选择其心脏对高原低氧环境的适应不同于藏系绵羊。
AIM： To investigate the characteristics of adaptation of the heart to high altitude in Tibetan antelope.METHODS： Both Tibetan antelope and Tibetan sheep were captured at altitude of 4 300 m and then transported to Gurmud（2 800 m）,where the study was conducted immediately after arrival.The heart rate（HR）,systolic blood pressure（SBP）,diastolic blood pressure（DBP） and the maximum rate of change in left ventricular pressure（±dp/dt） were measured directly by cardiac catheterization.After the baselines of the parameters were obtained,the animals were inhaled hypoxic gas of 14.6% O2 or 12.5% O2,which was simulated to the altitudes of 5 300 m and 6 300 m,and then those measurements were repeated within 15 min.The ratios of heart weight to body weight（HW/BW） and right to left ventricular plus septum weights [RV/（LV＋IVS）] were determined.The Ultra-structural changes of the cardiac muscle were also observed under electron microscope.RESULTS： The HW/BW of Tibetan antelope was significantly greater than that of Tibetan sheep（P0.01）,and no difference of RV/（LV＋IVS） was observed between both animals.At baselines,HR and SBP of Tibetan antelope [（26.30±6.15） beats/min,（97.75±9.56）mmHg] were significantly lower than those of Tibetan sheep [（34.30±6.57） beats/min,（130.06±17.79）mmHg].The value of ＋dp/dt in Tibetan antelope [（633.87±159.49）mmHg/s] was similar to that of Tibetan sheep [（564.76±229.03）mmHg/s].However,after inhaled 14.6% or 12.5% hypoxic-gas for simulating the altitudes of 5 300 m and 6 300 m,the ＋dp/dt of Tibetan antelope was significantly increased to 145.1% and 148.1% respectively,while the Tibetan sheep was decreased to 68.4% and 70.5% of those in normoxia condition,respectively.Ultra-structural changes of the cardiac muscle indicated that there were more abundant mitochondria in the myocardium of the Tibetan antelope than those in the Tibetan sheep.CONCLUSION： The heart functions of Tibetan antelope are well adapted to hypoxic environment in the high altitude by increasing myocardial weight and mitochondria.On the other hand,the cardiac contractility of Tibetan antelope is normal in the rest,but obviously increases under stress conditions.
出处
《中国病理生理杂志》
CAS
CSCD
北大核心
2010年第8期1498-1502,共5页
Chinese Journal of Pathophysiology
基金
国家自然科学基金资助项目(No.30660052)
关键词
藏羚羊
藏系绵羊
高原低氧适应
心室功能
左
Tibetan antelope
Tibetan sheep
High altitude hypoxia adaptation
Ventricular funtion
left
