冷冻解除在体动脉痉挛的实验研究

Experimental study of relieving arterial spasm by vascular freezing

目的 探讨液氮冷冻解除动脉痉挛的可能性。方法 取 72只SD大鼠 ,体重 2 5 0～ 3 5 0g ,按手术先后随机分为 2项实验 ,每项实验 3 6只。实验A :显露右侧股动脉通过机械刺激使其强烈收缩后 ,用液氮冷冻血管。左侧股动脉不做任何处理作为对照。实验B :显露、切断并吻合右侧股动脉 ,机械刺激使血管强烈收缩后液氮冷冻吻合口。左侧股动脉切断后再吻合作为对照。 2项实验分别于术后即刻、3、10、2 1、3 0和 60d 6个时间组观察血管通畅率、血管口径的变化、血管对致痉刺激的反应及冷冻后血管的病理变化。结果 在A、B两实验中 ,血管吻合后的通畅率冷冻组与对照组的差异无显著意义 (P >0 .0 5 )。冷冻复温后 10s血管明显扩张并长时间保持在扩张状态 ,口径平均扩张 0 .42mm。组织学检查显示冷冻对血管壁有明显的损害。冷冻 3d后 ,血管内膜层内皮细胞和中膜层的平滑肌细胞大部分变性坏死或缺失。冷冻 2 1d后 ,血管壁各层基本修复 ,但中膜层的细胞数目减少 ,排列紊乱。血管各层有轻微的纤维化 ,无管腔狭窄和动脉瘤形成。结论 冷冻能有效解除血管痉挛。虽然冷冻对血管壁有明显损害 ,但是血管的通畅率仍然很高。

Objective To investigate the possibility of relieving arterial spasm by vascular freezing with liquid nitrogen.Methods Seventy-two SD rats weighing 250～350 g were divided into two experiments (36 animals in each). Experiment A:the right femoral artery was exposed and stimulated mechanically, after the vessel contracted intensively, it was frozen using liquid nitrogen. The left femoral artery served as control without any disposal. Experiment B:the right femoral artery was exposed, dissected, and then anastomosed. After femoral arteries contracted intensively by mechanical stimulation, anastomosis stoma was frozen by liquid nitrogen. The left femoral artery was transected and anastomosed as control. The patency rate, changes of vessel diameter, vascular response on spasm-producing stimulation and pathological changes were recorded right after,3,10,21,30 and 60 days after operation, respectively. Results There was no statistically significant difference in the patency rate between freezing group and control group. Ten seconds after artery freezing and the rewarming, blood vessel dilated evidently and lasted for a long time with an average increase of 0.42 mm in diameter. Pathologic examinations showed that freezing obviously damaged blood vessel wall. At 3 days, major degeneration, necrosis or disappearance occurred in the endothelium cell in the intima layer and smooth cell in the media layer. At 21 days, the repair of 3 layers of the artery wall was almost completed. But the cell number reduced markedly in the media layer and disarranged. Fibrosis in all layers of vascular wall was slight. There was no lumen narrowness and aneurysm formation. Conclusion Vascular freezing could relieve the vessel spasm effectively. Although vascular freezing obviously damage vascular wall, the patency rate is still very high.