超声心动图观察慢性间歇性低氧新西兰兔左心结构和功能的实验研究

发布时间：2019-02-23 15:31

【摘要】：目的：建立慢性间歇性低氧（CIH）新西兰兔模型，在二维超声及M型超声心动图技术观察左心常规结构和功能的基础上，进一步应用频谱多普勒、组织多普勒成像等彩色多普勒超声技术来观测CIH新西兰大白兔早期血流动力学和左心收缩、舒张功能及结构动态变化过程。方法：将新西兰兔置于CIH舱内，通过气体控制系统向CIH舱内循环通入氮气和氧气以模拟慢性间歇性低氧环境，1次循环时间为170s，使舱内氧浓度波动于8～21%，即充入氮气使CIH舱内氧浓度由21%下降至8～12%，约需80s，维持在最低氧浓度，持续约25s；随后充入氧气升高CIH舱内氧浓度，使CIH舱内氧浓度恢复到21%，约需35s，并维持约25s，至下一循环。每天持续6小时（h），6天/周（d/w），共8周（w）。应用GE-Vivid7型彩色超声诊断仪于造模第0、1、2、4、6、8w进行超声心动图检查。心肌及主动脉标本送病理学检查，HE染色观察形态学变化。结果：①左室结构变化：与0w比较，1w、2w、4w时各参数无统计学意义（P＞0.05）,6w、8w时LVPW、IVS增厚，差异有统计学意义（P＜0.05），8w时LVEDd、LV（左右径）、LA（前后径）、LA（左右径）增大，AO增宽，差异有统计学意义（P＜0.05）。②左室收缩功能参数：EF（Simpson法）于2w和4w升高（P＜0.05），6w、8w逐渐减低，，但与0周比无统计学意义（P＞0.05），IVCT于1w、2w和4w时缩短（P＜0.05），ET于4w缩短（P＜0.05），IVS-Sm于2w、4w、6w增高（P＜0.05）。③左室舒张功能参数：与0w比较， MV E峰、IVS-Em于2w、4w升高，8w减低，IVS-Am于8w增高，IVS-Em/Am于4w升高，8w减低（P＜0.05），IVRT于1w、2w、4w缩短，8w时延长（P＜0.05），DT于8w延长，Vp于8w减低（P＜0.05），Adur在各时间点差别无统计学意义（P＞0.05）。④左室心肌病理改变：0w时心肌细胞完整，排列整齐，无血管扩张及血管壁增厚等表现；2w、4w时镜下可见心肌纤维排列略显紊乱，心肌细胞轻度肿胀，细胞核体积轻度增大，间隙略增宽，细胞间质轻度水肿；6w，8w时镜下可见心肌细胞肥大，细胞核增大，心肌纤维增粗且排列紊乱、间隙增宽，部分细胞可见空泡变性，胞浆溶解，细胞间质充血水肿。结论：①IVCT和IVRT是反映CIH新西兰兔左室收缩和舒张功能代偿的敏感性指标。②左心对CIH的应答呈时间依赖性，先发生了独立于左室壁增厚的收缩舒张功能代偿，之后左室功能代偿依赖于左室结构的改变。③左室舒张功能受损早于收缩功能。
[Abstract]:Objective: to establish a new Zealand rabbit model of chronic intermittent hypoxic (CIH) and to observe the conventional structure and function of the left heart by two dimensional echocardiography and M-mode echocardiography. Tissue Doppler imaging and other color Doppler ultrasound techniques were used to observe the dynamic changes of hemodynamics and left ventricular systolic diastolic function and structure in CIH New Zealand rabbits. Methods: the New Zealand rabbits were placed in the CIH cabin, and the nitrogen and oxygen were circulated through the gas control system to simulate the chronic intermittent hypoxic environment. The cycle time was 170 s, and the oxygen concentration in the chamber fluctuated at 821 h. The oxygen concentration in the CIH chamber was decreased from 21% to 812 seconds, which was maintained at the lowest oxygen concentration for about 25 s. Then the oxygen is filled to increase the oxygen concentration in the CIH chamber, so that the oxygen concentration in the CIH chamber recovers to 21. It takes about 35 seconds and maintains about 25 seconds to the next cycle. Daily duration of 6 hours (h), 6 days / week (d / w), a total of 8 weeks (w). Echocardiography was performed by using GE-Vivid7 color ultrasound diagnostic instrument at the 0th week of model making. The myocardial and aortic specimens were examined by pathology and the morphological changes were observed by HE staining. Results: 1the changes of left ventricular structure: there was no significant difference in the parameters of the left ventricular structure between the two groups (P > 0. 05), but there was no significant difference in the thickness of LVPW,IVS at 6 and 8 weeks (P < 0. 05), and the LVEDd,LV (left and right diameter) at 8 weeks. LA (anteroposterior diameter), LA (left and right diameter) increased and AO widened (P < 0. 05). The left ventricular systolic function parameter (: EF (Simpson method) increased at 2 and 4 weeks (P < 0. 05), and gradually decreased at 6 and 8 weeks. But there was no significant difference between 0 and 0 weeks (P > 0. 05), IVCT at 1 and 4 weeks) (P < 0. 05), ET at 4 weeks), IVS-Sm at 2 ws and 4 ws. 3 left ventricular diastolic function parameters: compared with 0 w, IVS-Em increased at 4 weeks, decreased at 8 weeks, IVS-Am increased at 8 weeks, IVS-Em/Am increased at 4 weeks and decreased at 8 weeks (P < 0. 05), IVRT at 1 week, P < 0. 05), and left ventricular diastolic function increased at 6 weeks (P < 0. 05). At 2 weeks, 4 weeks, 8 weeks later (P < 0. 05), Vp decreased at 8 weeks (P < 0. 05), but decreased at 8 weeks (P < 0. 05), and decreased at 8 weeks (P < 0. 05). There was no significant difference in Adur at different time points (P > 0. 05). 4 the pathological changes of left ventricular myocardium were as follows: myocardial cells were intact and arranged at 0 w, without vasodilation and wall thickening. At 2 weeks after 4 weeks, the arrangement of myocardial fibers was slightly disordered, the myocardial cells were slightly swollen, the nuclear volume was slightly enlarged, the gap was slightly widened, and the interstitial cells were slightly edema. At 6 weeks or 8 weeks, myocytes were hypertrophy, nucleus was enlarged, myocardial fibers were thicker and disarranged, gap widened, vacuolar degeneration was observed in some cells, cytoplasm was dissolved, and interstitial hyperemia and edema were observed. Conclusion: 1IVCT and IVRT are sensitive indexes to reflect left ventricular systolic and diastolic function compensation in CIH New Zealand rabbits. 2 the response of left ventricular to CIH is time-dependent, and the systolic and diastolic function compensations are independent of left ventricular wall thickening. After that, left ventricular function compensation depended on the change of left ventricular structure. 3 left ventricular diastolic function was damaged earlier than systolic function.
【学位授予单位】：山西医科大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R540.45

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