Ultrastructural changes of the wall of femoral vein after simulated weightlessness in rabbits

Yong YUE; Dongfeng ZHAO; Yongjie YAO; Chunmei WANG; Xiqing SUN; Xingyu WU

ABSTRACT

BACKGROUND:

At present, most researches on simulated weightlessness are confined to its effect on the artery. Therefore, the effect on the vein needs to be further studied.

OBJECTIVE:

To probe into the effect of simulated weightlessness on the ultrastructure of rabbit femoral vein and the remodeling of femoral vein.

DESIGN:

A completely randomized and controlled trial based on experimental animals.

SETTING:

Department of Aerospace and Aviation Medical Science, Fourth Military Medical University of Chinese PLA.MATERIALS The experiment was completed in the Department of Aerospace and Aviation Medical Science, Fourth Military Medical University of Chinese PLA from December 2000 to December 2001. Altogether 24healthy male New Zealand rabbits, weighing 2.0-2.5 kg were obtained.

INTERVENTIONS:

The model of Head-Down Tilt( -20°) (HDT) simulated weightlessness was established in rabbits. A total of 24 healthy male New Zealand rabbits were randomly divided into control group, 10-day simulated weightlessness group and 21-day simulated weightlessness group, with 8rabbits in each group. The ultrastructure of the rabbit femoral vein was observed under transmission electron microscope.MAIN OUTCOME

MEASURES:

Changes and degeneration of endothelial cell, mitochondrion, internal elastic membrane, and smooth muscle.

RESULTS:

Cell organelles in endothelial cell of the femoral vein of HDT rabbits decreased, mitochondrion dissolved and disappeared, vacuolar degeneration in endothelial cell increased and phagolysosome in endothelial cell could be found. Internal elastic membrane became thinner and was broken. The smooth muscle layer became thinner and some smooth muscle cells became degenerated. Cell interstitial substance increased. There was significant difference in changes between 21-day and 10-day simulated weightlessness groups.

CONCLUSION:

The vascular remodeling of femoral vein occurs with atrophic changes during simulated weightlessness. The longer duration of simulated weightlessness is, the more obviously the structure of femoral vein changes.