title: [Effects of simulated weightlessness on pressure-volume relationships of femoral vein of New Zealand Rabbits].
abstract: Objective. To observe the changes of pressure-volume relationships of rabbit femoral veins and their structural changes caused by simulated weightlessness. Method. Head-Down Tilt (HDT) -20 degrees rabbit model was used to simulate weightlessness. Twenty four healthy male New Zealand Rabbits were randomly divided into 21 d HDT group,10 d HDT group and control group, (8 in each group). Pressure-volume (P-V) relationship of rabbits femoral veins was measured and the microstructure of the veins was observed. Result. The femoral vein P-V relationship curves of HDT groups showed a larger volume change ratio than that of control group. This change was that 21 d HDT group was even more obvious than that of HDT-10 d group. B1 and B2 in quadratic equations of 21 d HDT group were significantly higher than the values of both 10 d HDT group and control group during expansion (inflow) and collapse (outflow) (P<0.01). The result of histological examination showed that the contents and structure of femoral vein wall of HDT-rabbits changed significantly. Endothelial cells of femoral vein became short and columnar or cubic, some of which fell off. Smooth muscle layer became thinner. Conclusion. Femoral venous compliance increased after weightlessness-simulation and the femoral venous compliance in 21 d-HDT rabbits increased more obviously than that in 10 d-HDT rabbits. The structure of femoral vein wall had changed obviously.
authors.forename: Yong
authors.initials: Y
authors.lastname: Yue
authors.forename: Yong-jie
authors.initials: YJ
authors.lastname: Yao
authors.forename: Xiao-ping
authors.initials: XP
authors.lastname: Xie
authors.forename: Bing
authors.initials: B
authors.lastname: Wang
authors.forename: Qing-sheng
authors.initials: QS
authors.lastname: Zhu
authors.forename: Xing-yu
authors.initials: XY
authors.lastname: Wu
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D003187:Compliance; D004847:Epithelial Cells / Q000502:physiology; D005268:Femoral Vein / Q000166:cytology* / Q000502:physiology*; D018475:Head-Down Tilt; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000502:physiology; D011312:Pressure; D011817:Rabbits; D012044:Regression Analysis; D018474:Weightlessness Simulation