Influence of intermittent plateau hypoxia/reoxygenation on rat heart

Cai Mingchun; Huang qingyuan; Xu Guang; Luo Yongchang; Gao Yuqi

doi:10.3969/j.issn.1674-4055.2019.11.09

Abstract：understand the influence of intermittent hypoxia/reoxygenation on rat heart in plateau environment through observing the heart structure and hemodynamic changes in rats exposed to intermittent hypoxia/reoxygenation. Methods The model of plateau hypoxia was established by applying hypobaric chamber. Male adult SD rats (n=50) were divided randomly into 5 groups: plain control group (group C), chronic hypoxia group [group H, in simulated lower pressure environment (altitude of 5000 m) for 8 weeks], intermittent hypoxia group (group I, in the same environment as group H, except of reducing simulated altitude to plain for 2 h in the morning and afternoon and setting at 2700 m for 8 h at night every day), 1-week chronic hypoxia group (group Hw, returned to plain for 1 week), and 1-week intermittent hypoxia group (group Iw, returned to plain for 1 week). The left ventricular function and right ventricular function were detected by using cardiac catheter, and activity of myocardial superoxide dismutase (SOD) and content of malondialdehyde (MDA) were detected by using colorimetry. Results The right ventricular maximum pressure (RVMP) and right ventricular hypertrophy index increased significantly in group H, group I and group Hw (P<0.05), and had no significant changes in group Iw compared with group C, and they decreased significantly in group I and Iw group compared with group H and group Hw (P<0.05). The activity of SOD decreased significantly in group H, group I and group Hw compared with group C (P<0.05). The content of MDA increased significantly in group H (P<0.05) and had no significant changes in group I, group Hw and group Iw. Conclusion The intermittent oxygen supply in long-term plateau hypoxia environment can reduce right ventricular pressure and relieve ventricular hypertrophy and damage due to oxygen free radicals, which is propitious to the recovery of heart structure and function after returning to plain.