模拟失重大鼠大脑中动脉与肠系膜小动脉生物力学行为的比较

发布时间：2018-08-13 16:09

【摘要】：为进一步阐明短期失重下血管的适应性改变及其重力性对抗措施的机理,本文对3d模拟失重组(SUS)、对抗措施组(STD,每日恢复正常站立体位1h模拟-Gx重力)及对照组(CON)大鼠大脑中动脉和肠系膜第三级小动脉的被动和主动生物力学特性进行了分析。所研究的生物力学参数包括:被动血管的表观刚度(β)、被动和主动血管的周向应力(σθ)-应变(εθ)关系及其增量弹性模量(Einc,p),和平滑肌收缩活动所致的激活增量弹性模量(Einc,a)。主动血管生物力学特性分析结果显示,肌源性紧张度的调节对失重下血管的适应具有重要意义:(1)SUS组肠系膜第三级小动脉的主动σθ-εθ曲线与其被动态曲线基本一致,表明通过肌紧张度调节使σθ恢复正常的功能基本丧失;但每日1h的-Gx重力暴露则可完全防止此功能减退;(2)SUS组大脑中动脉的主动σθ-εθ曲线较其被动曲线明显左移,不同压力下εθ始终相对稳定,σθ也趋于正常;且每日短时-Gx重力不能防止这种功能亢进。另一方面,对被动血管生物力学特性的分析则提示,不同血管的间质成分可能有不同重塑(remodeling)变化,如失重暴露时间进一步延长,将可能观察到有显著意义的重要变化。总之,本文血管生物力学特性分析对阐明失重环境下血管适应机理及其重力性对抗措施具有重要意义。
[Abstract]:In order to further elucidate the adaptive changes of blood vessels under short-term weightlessness and the mechanism of gravity countermeasures, The passive and active biomechanical properties of the middle cerebral artery and mesenteric arterioles of (CON) rats in 3D simulated weightlessness group (STD, 1 h postural position 1 h daily simulated Gx gravity) and control group were analyzed. The biomechanical parameters studied include the apparent stiffness (尾) of the passive vessels, the relationship between the circumferential stress (蟽胃) and strain (蔚胃) of the passive and active vessels and the incremental elastic modulus (Einca), and the activated incremental elastic modulus (Einca) caused by the contraction of smooth muscle. The results of biomechanical analysis of active blood vessels showed that the regulation of myogenic tenderness was of great significance to the adaptation of the vessels under weightlessness: (1) the active 蟽胃-蔚胃 curve of the third small mesenteric artery in the SUS group was basically consistent with the dynamic curve of the mesenteric artery. The results showed that the function of 蟽胃 returning to normal was basically lost through muscle tension regulation, but the Gx gravity exposure for 1 hour per day could completely prevent the decline of the function. (2) the active 蟽胃-蔚 curve of the middle cerebral artery in SUS group shifted significantly to the left compared with the passive curve. Under different pressures, 蔚胃 is relatively stable and 蟽胃 tends to be normal, and short-term Gx gravity cannot prevent this kind of hyperactivity. On the other hand, the analysis of the biomechanical properties of passive blood vessels suggests that the interstitial components of different blood vessels may have different remodeling (remodeling) changes. If the exposure time of weightlessness is further prolonged, significant changes may be observed. In conclusion, the analysis of vascular biomechanical characteristics in this paper is of great significance in elucidating the mechanism of vascular adaptation and its gravity countermeasures in weightlessness environment.
【作者单位】：第四军医大学航空航天医学教育部重点实验室航空航天生理学教研室;克兰菲尔德大学航空工程系;
【基金】：supported by the National Natural Science Foundation of China(No.30570677,30470649)
【分类号】：R85

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