Zhang L F, Chen J E, Ding Z P, Ma J
Laboratory of Applied and Systems Physiology, Institute of Basic Medical Sciences, Xi'an, P.R. China.
Physiologist. 1993 Feb;36(1 Suppl):S26-7.
The aim of our serial work was to investigate the cardiovascular deconditioning effect of long-term simulated weightlessness and to elucidate its mechanisms. Our research goal was established in view of the following three reasons. Firstly, even after several decades of extensive research, there still exist significant gaps in our knowledge concerning microgravity induced cardiovascular effect. Secondly, to guarantee the health and safety of astronauts in the future prolonged missions, it is important to understand the cardiovascular adaptation to long-term weightlessness. Thirdly, the reported ultrastructural degenerative changes in myocardium of rats flown on the Cosmos 1887 biosatellite has raised concerns about the question whether long-term spaceflight may lead to myocardial degeneration. To achieve this, we considered an appropriate animal model to simulate cardiovascular and other effects of long-term microgravity was of first importance. By making some modifications to the Morey-Holton's model, a method of long-term tail-suspension with less stressful influence and no injurious effects on the tail skin was developed. Up to now, the longest period of suspension in our laboratory has been of 120-day long. In this paper, we will focus primarily on the findings from our recent works on the cardiovascular deconditioning effect of 90-/120-day tail-suspension and changes in baroreflex responsiveness and in contractility and ultrastructure of the heart in rats.
我们系列研究的目的是探讨长期模拟失重对心血管系统的去适应作用，并阐明其机制。基于以下三个原因确立了我们的研究目标。其一，尽管经过数十年的广泛研究，但在微重力对心血管系统影响方面，我们的认识仍存在重大空白。其二，为确保未来长期任务中宇航员的健康与安全，了解心血管系统对长期失重的适应情况至关重要。其三，关于“宇宙1887”生物卫星搭载飞行的大鼠心肌超微结构退行性变化的报道，引发了人们对长期太空飞行是否会导致心肌退变这一问题的担忧。为实现这一目标，我们认为选择合适的动物模型来模拟长期微重力对心血管及其他方面的影响至关重要。通过对莫雷 - 霍尔顿模型进行一些改进，开发出一种对尾部压力影响较小且对尾部皮肤无损伤的长期尾部悬吊方法。到目前为止，我们实验室最长的悬吊时间为120天。在本文中，我们将主要关注近期关于90/120天尾部悬吊对大鼠心血管去适应作用、压力反射反应性以及心脏收缩性和超微结构变化的研究结果。
