Sun Yanqiu, Zhang Chenhong, Tian Dengfeng, Bai Junhu, Li Yaodong, Yu Xiaosheng, Yang Jing, Wang Xueling, Dong Yongxing, Yang Mei, Kang Zhiqiang, Zhang Qiang, Gao Fabao
Department of Radiology, Qinghai Provincial People's Hospital, Xining, China.
Department of Neurosurgery, Qinghai Provincial People's Hospital, Xining, China.
Ann Transl Med. 2021 Oct;9(20):1585. doi: 10.21037/atm-21-5078.
Long-term exposure to a high-altitude environment with low pressure and low oxygen can cause abnormalities in the structure and function of the heart, in particular the right ventricle. Monitoring the structure and function of the right ventricle is therefore essential for early diagnosis and prognosis of high-altitude heart-related diseases. In this study, 7.0 T MRI is used to detect cardiac structure and function indicators of rats in natural plateau and plain environments.
Rats in two groups were raised in different environments from 6 weeks of age for a period of 12 weeks. At 18 weeks of age both groups underwent 7.0 T cardiac magnetic resonance (CMR) scanning. Professional cardiac post-processing software was used to analyze right ventricular end-diastolic volume (RVEDV), right ventricular end-systolic volume (RVESV), right ventricular stroke volume (RVSV), right ventricular ejection fraction (RVEF), Right ventricular end-diastolic myocardial mass (RV Myo mass, diast), Right ventricular end-systolic myocardial mass (RV Myo mass, syst), tricuspid valve end-diastolic caliber (TVD), tricuspid valve end-systolic caliber (TVS), right ventricular end-systolic long-axis (RVESL) and right ventricular end-diastolic long-axis (RVEDL). Prior to the CMR scan, blood was collected from the two groups of rats for evaluation of blood indicators. After the scan, the rats were sacrificed and the myocardial tissue morphology observed under a light microscope.
In the group of rats subject to chronic hypoxia at high altitude for 12 weeks (the plateau group), red blood cell (RBC) count, hemoglobin (HGB) and hematocrit (HCT) increased (P<0.05); RVEDV, RVESV, RVSV, RV Myo mass (diast), RV Myo mass (syst), TVS, RVESL, and RVEDL also increased (P<0.05). Observation of the right ventricle of rats in the plateau group using a light microscope mainly showed a slightly widened myocardial space, myocardial cell turbidity, vacuolar degeneration, myocardial interstitial edema, vascular congestion and a small amount of inflammatory cell infiltration.
The importance of ultra-high-field MRI for monitoring the early stages of rat heart injury has been demonstrated by studying the changes in the structure and function of the right ventricle of rats subject to chronic hypoxia at high altitude over a period of 12 weeks.
长期暴露于低压低氧的高原环境会导致心脏结构和功能异常，尤其是右心室。因此，监测右心室的结构和功能对于高原心脏相关疾病的早期诊断和预后至关重要。在本研究中，采用7.0 T磁共振成像（MRI）检测自然高原环境和平原环境下大鼠的心脏结构和功能指标。
两组大鼠从6周龄起在不同环境中饲养12周。18周龄时，两组大鼠均接受7.0 T心脏磁共振（CMR）扫描。使用专业的心脏后处理软件分析右心室舒张末期容积（RVEDV）、右心室收缩末期容积（RVESV）、右心室每搏输出量（RVSV）、右心室射血分数（RVEF）、右心室舒张末期心肌质量（RV Myo mass, diast）、右心室收缩末期心肌质量（RV Myo mass, syst）、三尖瓣舒张末期口径（TVD）、三尖瓣收缩末期口径（TVS）、右心室收缩末期长轴（RVESL）和右心室舒张末期长轴（RVEDL）。在CMR扫描前，采集两组大鼠的血液以评估血液指标。扫描后，处死大鼠并在光学显微镜下观察心肌组织形态。
在高原慢性缺氧12周的大鼠组（高原组）中，红细胞（RBC）计数、血红蛋白（HGB）和血细胞比容（HCT）升高（P<0.05）；RVEDV、RVESV、RVSV、RV Myo mass（diast）、RV Myo mass（syst）、TVS、RVESL和RVEDL也升高（P<0.05）。光学显微镜下观察高原组大鼠的右心室，主要表现为心肌间隙稍增宽、心肌细胞浑浊、空泡变性、心肌间质水肿、血管充血及少量炎性细胞浸润。
通过研究高原慢性缺氧12周大鼠右心室结构和功能的变化，证明了超高场MRI在监测大鼠心脏损伤早期阶段的重要性。
