摘要
目的 探讨剪切力活化血小板的作用机制。方法 用改制的锥板黏度计对健康人的全血标本分别施加 10 0、15 0、10 0 0、30 0 0s-1的剪切力作用后 ,以血小板膜糖蛋白 (GP)的荧光标记抗体、单色或三色荧光法染色血小板 ,用流式细胞术检测血小板膜PAC 1(活化的GPIIb/IIIa)、CD6 2P(P 选择素 )、GPIb/IX和GPIIb/IIIa的水平。结果 PAC 1、CD6 2P在静止的血小板表面表达很低 ,阳性率分别为 1 7%± 1 1% (n =5 )和 0 9%± 0 5 % (n =5 ) ;受到高剪切力作用后表达水平增加 ,以PAC 1增加更为迅速、明显 ,于 30 0 0s-1剪切力作用 0 5min时达峰值 (73 6 %± 7 4 % ) ,之后很快开始下降 ,CD6 2P的表达相对较缓慢 ,但在观察时间内呈持续上升趋势 ,30 0 0s-1剪切力作用 7min时 ,阳性率为2 6 4 %± 3 5 %。GPIb/IX、GPIIb/IIIa存在于 96 5 %～ 99 4 %的静止血小板表面。血小板膜GPIb/IX水平在低剪切力作用下无明显变化 ,高剪切力作用 1min内有不同程度增加 ,但随后开始下降 ,30 0 0s-1作用 7min时 ,平均荧光强度由静止时的 72 4± 6 7降低到 4 4 9± 4 9(n =5 )。GPIIb/IIIa水平在高剪切力作用下迅速增加 ,30 0 0s-1作用 7min时 ,平均荧光强度由静止时的 98 5± 12 1增高到 15 9 5±2 3 6 (n =5 )。结论 高?
Objective To investigate the mechanism of activation of platelet by shear stress. Methods Specimens of whole blood were exposed to shear stress of different intensity (100, 150, 1 000, and 3 000 s -1 ) by modified cone and plate rotational viscometer. Then the platelets were stained with fluorescent antibody technique by flow cytometry to examine the levels of four kinds of platelet membrane glycoproteins : PAC 1, CD62P, GPIb/IX, and GPIIb/IIIa. Results The expression of PAC 1 and CD62P on the surface of unactivated platelets was very low, with the rates of 1.7%±1.1% ( n =5) and 0.9%±0.5% ( n =5) respectively. When the platelets were exposed to high shear stress, the expression of these two kinds of glycoproteins increased. The level of PAC 1 increased quickly and obviously in a short time, reached the peak value, 73.6%±7.4%, in half a minute after exposure to the shear stress of 3 000 s -1 and decreased soon. The expression rate of CD62P was low when the platelets were exposed to low shear stress, and then increased slowly along with the increase of shear stress. After exposure to the shear stress of 3 000 s -1 for 7 minutes, the expression rate of CD62P reached 26.4%±3.5%. GPIb/IX and GPIIb/IIIa were found to exist on the surface of more than 96.5%～99.4% of unactivated platelets. No significant change of GPIb/IX expression was found at relatively low shear stress. When the shear stress increased, the expression rate of GPIb/IX increased to an extent in 1 minute, then decreased continually. The fluorescent intensity of GPIb/IX was 72.4 ±6.7 while unactivated, and decreased to 44.9±4.9 ( n =5) after exposure to the shear stress of 3 000 s -1 for 7 minutes. The expression of GPIIb/IIIa on surface of unactivated platelets, with fluorescent intensity of 98.5±12.1, began to increase under low intensity of shear stress. When the stress increased, GPIIb/IIIa expression increased quickly in a short time, and began to decrease in 7 minutes with the fluorescent intensity of 159.5±23.6 ( n =5) by then. Conclusion High shear stress causes change of expression of platelet membrane glycoproteins. Platelets are activated by high shear stress directly and independently, and the activation may be mediated by these glycoproteins.
出处
《中华医学杂志》
CAS
CSCD
北大核心
2002年第4期267-270,共4页
National Medical Journal of China
