缺氧性肺动脉高压新生大鼠右心功能的评价研究

Evaluation of right heart function in neonatal rats with hypoxic pulmonary hypertension

目的通过评价缺氧性肺动脉高压新生大鼠的右心功能,探讨其用于模拟新生儿缺氧性肺动脉高压右心室功能不全及右心衰竭的可行性。方法将新生大鼠随机分为缺氧性肺动脉高压(HPH)组与对照组,每组再按观察时间点分为3 d、7 d、10 d及14 d组,HPH组建立HPH模型后,同对照组分别于以上时间点测定右心室收缩压(RVSP)、右心室肥厚指数(RVHI)、等容收缩期右心室内压力最大上升速率(+dp/dtmax)与等容舒张期右心室内压力最大下降速率(-dp/dtmax),并在光镜下观察右心心肌组织结构变化。结果与对照组相比,HPH组自缺氧第3天即可观察到RVSP与+dp/dtmax值升高(P<0.05),并在整个缺氧时间段内随缺氧时间的延长而增长,而-dp/dtmax则呈现先增长后降低的趋势。自缺氧第7天RVHI的差异有统计学意义(P<0.05),且光镜下可观察到HPH组右心心肌细胞肥大、肌原纤维增粗丰富,至缺氧14 d时部分区域可见心肌纤维排列紊乱。结论缺氧性肺动脉高压新生大鼠在14天的缺氧时间内,主要表现为右心室心肌代偿性收缩力的增强,无明显右心衰竭表现,尚处于右心功能代偿期,因此缺氧性肺动脉高压新生大鼠可以反映HPH右心功能改变,但为期14天的缺氧不能理想地模拟新生儿缺氧性肺动脉高压右心功能不全及右心衰竭。

Objective To investigate the feasibility of simulating neonatal hypoxic pulmonary hypertension with right ventricular dysfunction or right heart failureby evaluating the right ventricular function of neonatal rats with hypoxic pulmonary hypertension.Methods Newborn rats were randomly divided into the hypoxic pulmonary hypertension(HPH)group and the control group,and each group was further divided into 4 smaller groups(3 days,7 days,10 days,and 14 days)according to the different observation time.The rats in the HPH modelwere established.The right ventricular systolic pressure(RVSP),the right ventricular hypertrophy index(RVHI),the maximal rate of the increase of right ventricular pressure(+dp/dtmax),the maximal rate of the decrease of right ventricular pressure(-dp/dtmax)were meas-ured and their right heart cardiac tissue was observed under light microscope at different observation time.Results Compared with the control group,the RVSP and+dp/dtmax in the HPH group increased from the third day of hypoxia(P<0.05),and increased with the prolongation of hypoxia time during the entire period.However,-dp/dtmax increased at the beginning and then decreased.The difference in RVHI became statistically significant(P<0.05)since the 7th day of hypoxia.Furthermore,the cardiomyocyte hypertrophy and thickened myofibrils could be found in the right heart in the HPH group,and some myocardial tissue was disorganized on the 14th day of hypoxia.Conclusion Hypoxic pulmonary hypertension neonatal rats mainly showed the compensatory strengthening of cardiac muscular contraction but not the right ventricular dysfunction or right heart failure.They were still in the compensated right heart failure stage.