Leaver H A, Schou A C, Rizzo M T, Prowse C V
Research & Development Section, Scottish National Blood Transfusion Service, Ellen's Glen Road, Edinburgh EH17 7QT, UK.
Platelets. 2006 Sep;17(6):368-77. doi: 10.1080/09537100600757216.
The mechanisms involved in storage-induced damage in platelets are not well understood, but membrane signalling via Ca2+ ion flux may affect mitochondrial H+ gradients and metabolism and the intrinsic pathways of cell death, platelet survival and function. In this study, the effects of blood bank storage conditions, including reduced plasma concentration and interrupted agitation, were evaluated in platelets from 136 healthy donors. Mitochondrial membrane potential (DeltaPsim), an indicator of intrinsic cell death, and its sensitivity to Ca2+ ionophore A23187, were monitored using JC-1 by flow cytometry and fluorescence microscopy. Platelet survival was examined using lactate dehydrogenase release, annexin V binding and caspase-3/7 activity. Decreased plasma concentration and interrupted agitation affected DeltaPsim and caspase-3/7. Over 7 days in 30% plasma DeltaPsim showed a significant reduction (86.3 +/- 1.1% platelets with polarised mitochondria day 1; 79.9 +/- 2.1% day 5; 75.1 +/- 3.8% day 7, P = 0.01 day 1 vs. day 7). Whilst DeltaPsim in agitated platelets in 100% plasma was unchanged up to day 7, interruption of agitation was associated with a 44% reduction in the proportion of platelets with polarised mitochondria after 5 days (56 +/- 11%). The Ca2+ sensitivity of DeltaPsim changed earlier: 5 microM A23187 caused a 20-30% change in the fraction of platelets with polarised mitochondria by day 5. Ca2+ sensitivity also increased during interrupted agitation and reduced plasma concentration. DeltaPsim also correlated with indicators of platelet death, caspase-3 activity and annexin V binding (correlation coefficients of 0.8). In conclusion, changes in Ca2+-sensitive DeltaPsim are involved in the initiation of storage-induced cell death signals that influence platelet count and function in vivo.
血小板储存诱导损伤所涉及的机制尚未完全明确，但通过Ca2+离子通量的膜信号传导可能会影响线粒体H+梯度、代谢以及细胞死亡、血小板存活和功能的内在途径。在本研究中，对136名健康供者的血小板评估了血库储存条件的影响，包括血浆浓度降低和搅拌中断。使用JC-1通过流式细胞术和荧光显微镜监测线粒体膜电位（ΔΨm），这是内在细胞死亡的一个指标，以及其对Ca2+离子载体A23187的敏感性。使用乳酸脱氢酶释放、膜联蛋白V结合和半胱天冬酶-3/7活性检测血小板存活情况。血浆浓度降低和搅拌中断会影响ΔΨm和半胱天冬酶-3/7。在30%血浆中储存7天，ΔΨm显著降低（第1天有极化线粒体的血小板为86.3±1.1%；第5天为79.9±2.1%；第7天为75.1±3.8%，第1天与第7天相比，P = 0.01）。虽然在100%血浆中搅拌的血小板的ΔΨm直至第7天保持不变，但搅拌中断与5天后有极化线粒体的血小板比例降低44%相关（56±11%）。ΔΨm对Ca2+的敏感性变化更早：到第5天，5μM A23187使有极化线粒体的血小板比例变化20 - 30%。在搅拌中断和血浆浓度降低期间，Ca2+敏感性也增加。ΔΨm还与血小板死亡指标、半胱天冬酶-3活性和膜联蛋白V结合相关（相关系数为0.8）。总之，Ca2+敏感的ΔΨm变化参与了储存诱导的细胞死亡信号的启动，这些信号会影响体内血小板计数和功能。
