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目的研究尾部悬吊模拟失重对大鼠肺循环的影响,为模拟失重对肺循环局部调节与立位耐力和运动能力降低机制研究积累资料。方法 -30°尾部悬吊(tail-suspension,TS)模拟失重的生理效应,Wistar雄性大鼠被随机分成3组:对照组(Con)、7d尾部悬吊组(TS7)和14d尾部悬吊组(TS14)。采用PowerLab/4SP生理记录系统记录肺动脉压、肺静脉压;超声流量计检测肺动脉流量。结果 TS7、TS14组大鼠肺动脉收缩压(arterial systolic blood pressure,SBP)显著降低(P<0.05),TS7组肺动脉舒张压(arterial diastolic blood pressure,DBP)有降低趋势,TS14组大鼠肺动脉DBP显著降低。TS7、TS14组大鼠肺动脉平均压(mean arterial pressure,MAP)均显著(P<0.05)或极显著降低(P<0.01)。TS7、TS14组大鼠静脉压变化不明显。TS7、TS14组大鼠平均动、静脉压压差显著减小主要为动脉端压力变化所致。TS14组大鼠心率(heart rate,HR)是血容量减少的代偿反应,TS7组每分肺动脉流量有增加趋势,可能为从初期反应期到基本适应期肺循环的超调现象所致。结论 TS7和TS14肺动脉端阻力和肺循环阻力显著减小主要起因于肺动脉端压力变化,可能是造成模拟失重后立位耐力和运动能力降低的原因。
Objective To study the effects of tail suspension simulated weightlessness on pulmonary circulation in rats and to accumulate data on the mechanism of simulated weightlessness on the local regulation of pulmonary circulation and the mechanism of standing endurance and exercise capacity reduction. Methods -30 ° tail-suspension (TS) simulated the physiological effects of weightlessness. Wistar male rats were randomly divided into three groups: control group (Con), tail suspension group 7d (TS7) and tail suspension group 14d (TS14). Pulmonary artery pressure and pulmonary venous pressure were recorded by PowerLab / 4SP physiological recording system. Pulmonary artery flow was detected by ultrasonic flowmeter. Results The pulmonary arterial systolic blood pressure (SBP) was significantly decreased in TS7 and TS14 groups (P <0.05), the pulmonary artery diastolic blood pressure (DBP) in TS7 group was decreased, and the pulmonary artery DBP was significantly decreased in TS14 group reduce. The mean arterial pressure (MAP) in TS7 and TS14 groups was significantly (P <0.05) or significantly reduced (P <0.01). TS7, TS14 group venous pressure change was not obvious. The mean arterial pressure and venous pressure difference of rats in TS7 and TS14 groups decreased significantly, which was mainly caused by the change of arterial pressure. TS14 rats heart rate (heart rate, HR) is a compensatory response to blood volume reduction, TS7 per pulmonary artery flow rate increases, may be from the initial response period to the basic adaptation of the pulmonary circulation overshoot phenomenon. Conclusions The significant decrease of pulmonary end resistance and pulmonary circulation resistance in TS7 and TS14 is mainly attributed to the change of pulmonary end pressure, which may be the reason of the decrease of standing endurance and exercise capacity after simulated weightlessness.