失血性休克大鼠血管平滑肌细胞钙超载的三磷酸腺苷酶机制

Adenosine triphosphatase mechanism of calcium overload in vascular smooth muscle cell in hemorrhagic shock rats

目的 探讨失血性休克大鼠血管平滑肌细胞 (VSMC)钙超载的三磷酸腺苷 (ATP)酶机制。 方法 雄性Wistar大鼠 2 4只 ,随机分为对照组 (C组 )、休克开始组 (S0组 )、休克后 2 ,4h组 (分别为S2和S4组 ) ,每组 6只。以改良Wigger法 ,即股动脉插管放血并维持血压 4 0mmHg 2h建立失血性休克大鼠模型 ,观察休克后大鼠VSMC胞浆游离钙离子浓度及细胞膜、线粒体膜Ca2 +-ATPase ,Na+ -K+ -ATPase活性变化。 结果 C、S0、S2、S4组VSMC胞浆游离Ca2 + 浓度平均通道荧光对数值分别为 2 .0 3± 0 .15、2 .37± 0 .32、2 .5 5± 0 .4 6、2 .80± 0 .4 3,呈休克时间依赖性升高 ,S0组显著大于C组 (P <0 .0 5 ) ,S2、S4组非常显著地大于C组 (P <0 .0 1)。细胞膜Ca2 + -ATPase活性 :C组为 (36 .0± 7.2 ) μmol·mg- 1 ·h- 1 ;S0组 [(35 .3± 8.5 ) μmol·mg- 1 ·h- 1 ]与C组比较 ,差异无显著性意义 ;S2、S4组分别为 (2 6 .5± 6 .9)、(2 4 .3± 4 .7) μmol·mg- 1 ·h- 1 ,均显著低于C组 (P <0 .0 5和P<0 .0 1) ;细胞膜Na+ -K+ -ATPase活性 :C组为 (34.0± 5 .8) μmol·mg- 1 ·h- 1 ;S0、S2组分别为 (37.3± 6 .9)、(32 .2± 6 .3) μmol·mg- 1 ·h- 1 ,与C组比较 ,差异无显著性意义 ;S4组为 (2 7.0±4 .9) μmol·

Objective To explore the mechanism of adenosine triphosphatase (ATPase) of calcium overload in vascular smooth muscle cell (VSMC) in hemorrhagic shock rats. Methods Twenty-four male Wistar rats were randomly divide into four groups: control (Group C), shock start (Group S0), 2 hours post-shock (Group S2) and 4 hours post-shock (Group S4). The rat models with hemorrhage shock were produced by means of modified Wigger's method through bloodletting from femoral artery and keeping blood pressure at 40 mm Hg for 2 hours. The changes of cytosolic free Ca 2+ concentration (i) and the activities of Ca 2+ - ATPase and Na +-K +- ATPase in VSMC membrane and mitochondrial membrane were monitored in rats after shock. Results Mean channel fluorescence values of VSMC i in the Groups C, SO, S2 and S4 were 2.03±0.15, 2.37± 0.32 , 2.55±0.46 and 2.80±0.43 respectively and increased in a time-dependent fashion. Mean channel fluorescence values of VSMC i in the Groups S0, S2 and S4 was significantly higher than that in the Group C ( P <0.05 and P <0.01).Ca 2+ -ATPase activities in the VSMC membrane was (36.0±7.2) _mol·mg -1 ·h -1 in the Group C and (35.3±8.5) _mol·mg -1 ·h -1 in the Group S0, without significant differences between both groups. Ca 2+ -ATPase activities in the VSMC membrane in the Groups S2 and S4 were (26.5±6.9) _mol·mg -1 ·h -1 and (24.3±4.7) _mol·mg -1 ·h -1 respectively, which was significantly lower than that in the Group C ( P <0.05 and P <0.01). Na +-K +-ATPase activities in the VSMC membrane in the Groups S0 and S2 was (37.3±6.9) _mol·mg -1 ·h -1 and (32.2±6.3) _mol·mg -1 ·h -1 respectively, without significant differences compared with that in Group C. Na +-K +-ATPase activities in the VSMC membrane in the Group S4 was (27.0±4.9) _mol·mg -1 ·h -1 , remarkably lower than that in the Group C ( P <0.05). Ca 2+ -ATPase activities in the mitochondrial membrane in the Groups S0,S2 and S4 were (10.7± 2.4) _mol·mg -1 ·h -1 , (13.5±3.1) _mol·mg -1 ·h -1 and (11.2±3.4) _mol·mg -1 ·h -1 respectively, which was all significantly higher than that in the Group C [(8.8±2.3) _mol·mg -1 ·h -1 ] ( P <0.05). Na +-K +-ATPase activities in the mitochondrial membrane in the Groups S0 and S2 were (10.1±1.7) _mol·mg -1 ·h -1 and (9.7± 1.8) _mol·mg -1 ·h -1 ,which was very significantly higher than that in the Group C [(5.3±1.1) _mol·mg -1 ·h -1 ] ( P <0.01). Na +-K +-ATPase activities in the mitochondrial membrane in the Group S4 was (7.3± 1.2) _mol·mg -1 ·h -1 , which was significantly higher than that in the Group C ( P <0.05). Conclusions That calcium overload occurs in VSMC in the hemorrhagic shock rats is most likely related to the activity decrease of Ca 2+ -ATPase and Na +-K +-ATPase in the VSMC membrane and the increase of that in the mitochondrial membrane during hemorrhagic shock.