等长收缩负荷对家兔股动脉固有侧支循环开放的影响

The effect of isometric contraction in opening femoral artery collateral circulation in rabbits

目的观察不同等长收缩负荷对股动脉固有侧支循环开放的影响，为研究生理性缺血训练对侧支循环生成的影响奠定基础。方法选择健康成年家兔24只，体重（2．0±0．5）kg，于左下肢坐骨神经植人电极，电刺激产生等长收缩造成缺血，预先设定不同收缩强度和时间。实验终止时取坐骨神经支配区——腓肠肌组织，微球技术定量检测股动脉固有侧支血流（FCBF）。结果①采用40％最大等长收缩强度（IEmax）时缺血区局部血流降低程度最大（P〈0．01）；采用60％IEmax和80％IEmax的局部血流下降率相比，差异无统计学意义。②采用40％IEmax刺激0～4min，FCBF呈增加趋势，第4分钟时达峰值，较刺激即刻、刺激后第2，3分钟明显增加（P〈0．01），至第5分钟不再进一步增加。③以40％IEmax刺激4min后再灌注0～2min，FCBF呈增加趋势，再灌注第2分钟FCBF较再灌注即刻明显增加（P〈0．01），第5分钟FCBF回落至基础水平，至第8，10分钟无显著变化。结论促使家兔股动脉FCBF最大开放的最小强度为40％IEmax，最短刺激时问为4min，FCBF开放持续时间不超过5min。

Objective To explore the effect of isometric contraction-induced ischemic burden for evoking maximal intrinsic femoral artery collateral circulation. Methods Twenty-four adult New Zealand rabbits weighing （2.0 ± 0.5 ） kg were subjected to a model of isometric contraction-induced ischemia. An electrode was implanted in the sciatic nerve of the left hind limb for evoking isometric contraction of the gastrocnemius, which blocked local blood flow and induced local isehemia. Femoral artery collateral blood flow （FCBF） was measured using a micro- sphere technique. Results Local blood flow was the lowest at 40% of the maximal isometric contraction （IEmax） , and reached plateau at 60% of lEmax. FCBF increased gradually and reached a plateau at 40% of IEmax in the 4th min. After 4 minutes at 40% of IEmax, FCBF had increased to higher than pre-stimulus, peaking in the 2nd minute, and then decreasing gradually to baseline at the 5th minute after reperfusion. It ceased to increase when reperfusion was prolonged to 8 or 10 min. Conclusions The minimal ischemic burden for full obstruction of the femoral artery is 40% of IEmax, and the shortest stimulus duration is 4 rain. The maximal FCBF opening duration is no more than 5 min.