摘要
目的:探讨大鼠腹主动脉血管平滑肌细胞(VSMCs)在缺氧培养时胞内钙库钙释放的变化情况,并探讨胞内钙库钙释放在休克血管对去甲肾上腺素(NE)低反应性中的可能作用,为进一步阐明休克血管低反应性的发生机制提供依据。方法:建立大鼠失血性休克(40mmHg,2h)的在体模型及大鼠VSMCs缺氧细胞模型;采用Fura-3/AM钙离子成像方法测定VSMCs胞浆钙离子浓度([Ca2+])的变化情况及其与IP3受体(IP3R)及雷诺定受体(RyR)介导的钙释放通道的关系;采用离体器官张力测定技术,检测不同内钙释放依赖信号通路在休克血管低反应性形成中的可能作用。结果:在细胞外液无Ca2+的前提下,NE可通过动员内钙释放引起VSMCs胞浆[Ca2+]的明显升高;缺氧培养后VSMCs胞浆[Ca2+]较正常对照组有所升高,由NE诱导的VSMCs胞浆[Ca2+]较对照组有所降低,但均无显著差别;但在缺氧培养的VSMCs,细胞内钙库钙释放功能明显改变,表现为与正常对照组比较,缺氧VSMCs由IP3R敏感钙释放通道开放剂adenophostinA(10-5mol/L)及ATP-Na2(10-4mol/L)诱导的VSMCs胞浆[Ca2+]升高不显著,但RyR敏感钙释放通道开放剂caffeine可诱导缺氧VSMCs胞浆[Ca2+]的明显升高;失血性休克(40mmHg,2h)可引起大鼠腹主动脉血管对由NE诱导的收缩反应性明显降低,IP3R激动剂ATP-Na2(10-4mol/L)并不明显提高休克血管对NE的收缩反应性,但IP3R阻断剂heparin(104U/L)可明显抑制休克血管对NE的收缩反应性;此外,在无钙及含钙的K-H液中,RyR阻断剂ryanodine(10-5mol/L)可部分恢复休克血管对NE的收缩反应性,而RyR激动剂caffeine(10-3mol/L)可进一步降低休克血管对NE诱导的收缩反应性。结论:失血性休克后由RyR介导的内钙释放被激活部分参与了休克血管低反应性的形成。
AIM:In order to investigate the mechanisms involved in the vascular hyporeactivity after hemorrhagic shock,the changes of Ca2+ release from calcium store in vascular smooth muscle cells(VSMCs)with hypoxia were observed and the role of Ca2+ release from calcium store in the occurrence of vascular hyporeactivity to norepinephrine(NE)after hemorrhagic shock in rats was further explored.METHODS:A hemorrhagic shock model(40 mmHg for 2 h)in rats and a VSMCs hypoxic model were established.The changes of intracellular Ca2+ concentration[Ca2+]in VSMCs were evaluated by fura3-AM and the role of IP3R and RyR mediated Ca2+ release from calcium store was further observed.The role of IP3R and RyR mediated Ca2+ release from Ca2+ store in the development of vascular hyporeactivity was measured with an isolated organ perfusion system.RESULTS:In the absence of extracellular Ca2+,NE upregulated[Ca2+]by mobilizing Ca2+ release through calcium store.Compared to the normal control,the VSMCs[Ca2+]had a slight increase when treated with hypoxia and NE-induced intracellular[Ca2+]down-regulated,both without significant difference.Compared to the normal control cells,there was a significant change of Ca2+ release from calcium store in hypoxia-treated VSMCs,characterized by the significant increase in[Ca2+]triggered by RyR-sensitive Ca2+ releasing activator caffeine.However,the increase in[Ca2+]triggered by IP3R-mediated Ca2+ release agonist adenophostin A(10-5 mol/L)and ATP-Na2(10-4 mol/L)had no significant difference in hypoxic VSMCs.Furthermore,the vascular reactivity to NE decreased in abdominal aorta in hemorrhagic shock(40 mmHg,2 h)rats.The activation of IP3R mediated Ca2+ release with ATP-Na2(10-4 mol/L)did not improve the vascular reactivity to NE,while inhibition of IP3R mediated Ca2+ release with heparin(104 U/L)significantly antagonized the vascular reactivity to NE in hemorrhagic shock rats.In addition,in normal K-H solution(with[Ca2+]about 2.2 mmol/L)and Ca2+-free K-H solution,RyR antagonist ryanodine(10-5 mol/L)partly restored
出处
《中国病理生理杂志》
CAS
CSCD
北大核心
2010年第A10期1873-1878,共6页
Chinese Journal of Pathophysiology
基金
国家重点基础研究规划资助项目(973)(No.2005CB522601)
关键词
休克
出血性
血管低反应
钙释放
Shock
hemorrhagic
Vascular hyporeactivity
Ca2+ release
