模拟失重大鼠比目鱼肌小动脉网各级血管内径的变化

Changes in Lumen Diameters of Vessels in Arteriolar Network in Rat Soleus Muscle after Simulated Weightlessness.

目的探讨模拟失重是否可引起后肢肌肉小动脉网各级血管内径发生改变及其可逆性。方法采用墨汁灌注法观察尾部悬吊４ｗｋ（ＳＵＳ４），悬吊４ｗｋ后恢复１ｗｋ（ＲＥＣ１）、恢复５ｗｋ（ＲＥＣ５），以及对照（ＣＯＮ）大鼠比目鱼肌小动脉网各级血管内径的变化。结果在ＳＵＳ４组，比目鱼肌的营养动脉、弓状小动脉及Ｖ、Ｉ级横行小动脉的内径，较ＣＯＮ组分别减小了３１％、２９％、２８％及４１％（均为Ｐ＜０．０１）；在ＲＥＣ１组，仅有部分恢复但仍普遍低于ＣＯＮ组（Ｐ＜０．０５，Ｐ＜０．０１）；在ＲＥＣ５组，除Ｉ级横行小动脉外，其余各级小动脉的内径均已恢复。结论４ｗｋ模拟失重大鼠后肢肌肉小动脉可能发生萎缩性变化。

Objective To elucidate whether simulated weightlessness can induce changes in lumen diameters of vessels in arteriolar networks in hindlimb muscles and whether these changes are reversible. Method Changes in lumen diameters of the vessels in the arteriolar network in soleus muscle of 4 wk tailsuspended (SUS4), 1 wk (REC1) and 5 wk (REC5) recovered rats were examined and compared with that of control (CON) rats by use of the method of intraarterial infusion of a carbon suspension. Result The lumen diameters of the feeding arteries and arcade arterioles, and the transverse arterioles of the order of both V and II in the SUS4 group were reduced by 31%, 29%, 28%, and 41%, respectively, as compared with that of the CON group ( P <0.01). The diameters of these arterioles in REC1 group were partially restored but remained significantly less than that of the CON group ( P <0.05, or P <0.01). In REC5 group, except for the transverse arterioles of order II, the diameters of all the other arterioles were fully recovered. Conclusion] These findings indicate that a 4 wk simulated weightlessness might induce atrophic changes in the arterioles of the hindlimb muscles.It also suggests that structural changes in arteriolar network might be an important mechanism accounting for postflight orthostatic intolerance.