兔主动脉粥样硬化后反应性的改变

用高胆固醇喂食造成兔主动脉粥样硬化模型,观察粥样硬化主动脉在离体灌流条件下反应性的改变。发现内壁完全为粥样斑块复盖的主动脉对乙酰胆碱(ACh)和降钙素基因相关肽(CGRP)的内皮依赖性舒张反应完全丧失,对去甲肾上腺素(NE)的最大收缩反应降低1.5倍(P<0.01),EC_(50)增大5.7倍(P<0.02),而对非内皮依赖性舒张物质异丙基肾上腺素的反应性没有改变。内壁部分复盖粥样斑块的主动脉对ACh的最大舒张反应降低43%(P<0.01),EC_(50)增大3倍(P<0.05),对NE的反应性也有降低趋势。而对CGRP的舒张反应无显著改变。上述结果提示粥样硬化动脉内皮依赖性舒张反应的丧失或降低可能是它们反应性改变的主要机制,但又不是唯一的机制。

Changes of vascular reactivity in the isolated rabbit aortae with atherosclerosis

The effects of atherosclerosis on vascular responses were studied in aortae isolated from rabbits which receiving the atherogenic diet for 14 weeks. The results showed that in the aorta rings in which the total intimal surfaces were covered with fatty streaks, the endothelium dependent relaxation to acetylcholine (ACh) and calcitonin generelated peptide (CGRP) were totally lost. The contractile response to norepinephrine (NE) Was reduced, which was shown by decreasing maximal relaxation dy 1.5-fold (P<0.01) and increasing CE_(50) by 5.7-fold (P<0.05), while the endothelium independent relaxation to isoproterenol (ISO) was not changed at all. In the aorta rings in which the intimal surfaces mere only partially covered with fatty streaks, the response to ACh was reduced, which was shown by decreasing maximal relaxation by 43%(P<0.01) and increasing EC_(50) by 3-fold (P<0.05). The response to NE also tended to be reduced. The responses to CGRP and ISO, however, were not changed. The results suggest that the impairments of endothelium mediated relaxation in atheroselerotic arteies might be the main, but not the only, mechanism for changes of vascular responses.