凝血酶诱导人类胚胎血管平滑肌细胞明胶酶分泌及活化

The secretion and activation of gelatinase induced by thrombin in cultured human embryonic vascular smooth muscle cells

目的 :探讨凝血酶对血管平滑肌细胞明胶酶合成及活化的影响。方法 :采用不同浓度的凝血酶(0.5、5、25、50u/ml)与培养的人类胚胎血管平滑肌细胞(HVSMC)或其条件培养上清液共育 ,用SDS -PAGE明胶酶谱法测定上清液中明胶酶的活性。结果 :浓度大于或等于5u/ml的凝血酶可以诱导HVSMC合成MMP -2,且呈剂量递增关系。0.5u/ml的凝血酶可激活proMMP -2,且随剂量增加而增强。剂量大于或等于25u/ml的凝血酶有诱导HVSMC合成MMP -9的作用。凝血酶与HVSMC条件培养液共育 ,证实凝血酶具有时间和剂量依赖性直接激活的作用。结论:凝血酶以剂量依赖性方式促进proMMP -2分泌 ,并对MMP -2有直接激活作用 ,提示局部凝血酶浓度升高可通过降解基质 。

Objective:To Investigate the effect of thrombin on expression and activation of gelatinase in human embryonic vascular smooth muscle cells(HVSMC). Methods: Thrombin at dose of 0.5～50u/ml was incubated with HVSMC or the culture medium collected from untreated HVSMC containing proMMP-2.The gelatinase(MMP-2 and MMP-9) in culture media were demonstrated by gelatin SDS-PAGE zymography.Results:When thrombin concentration ≥5u/ml, pro MMP-2 secretion were induced (P<0.01) and increased with the increasing thrombin concentration.Pro MMP-9 activity was found when thrombin concentration ≥25u/ml.The thrombin concentration as small as 0.5u/ml was able to activate pro MMP-2 and the effect increased positively with the thrombin concentration.Thrombin can directly activate the pro MMP-2 in a dose-dependent and time-dependent fashion.Conclusion:Thrombin promoted pro MMP-2 secretion in HVSMC and able directly activate pro MMP-2,which suggested that high concentration thrombin may induce vascular restenosis or atherosclerotic plaque instability.