Jak2在凝血酶诱血管平滑肌细胞增生中的作用

目的探讨凝血酶诱血管平滑肌细胞（vascular smooth muscle cells，VSMCs）异常增生的时相关系，及Jak2在其增生信号传递过程中的作用。方法本实验采用培养大鼠胸主动脉4—10代的VSMCs的单细胞悬液用于实验。用MTS法测VSMCs细胞增殖率。用免疫沉淀测定Jak2的活性。结果（1）0．5（u／ml）和1．0（u／ml）两种浓度的凝血酶相对于对照组，在各时间段均有明显促VSMCs增殖作用，且两者作用程度相似，增殖曲线呈双峰样改变，增殖峰在1h和24h。（2）凝血酶刺激组Jak2的活性在6h（P〈0．05）及12h（P〈0．05）均明显上升。相对于凝血酶组，AG490有效的降低了凝血酶诱导VSMCs1h峰值（P〈0．05）及24h峰值（P〈0．05）。结论（1）凝血酶促VSMCs的增殖在时间上呈双峰样改变，提示凝血酶不仅有早期快速促VSMCs的增殖作用．而且有后期促VSMCs的增殖作用。（2）由于Jak2活性高峰（6h及12h）在凝血酶促VSMCs第二增殖峰值（24h）之前。提示Jak2活性后期的增加参与了凝血酶促VSMCs后期增殖．

The role of Jak2 in thrombin-induced VSMCs proliferation

Objective To investigate the effect of thrombin on cultured vascular smooth muscle cells （VSMCs） proliferation and the role of Jak2 activity on thrombin-induced VSMCs proliferation.Methods Growth-arrested VSMCs （4-10 generation） were used in experiment.The activity of Jak2 in cells was assayed by immunoprecipitation.Cell proliferation was quantified by MTS method. Resuits （1） Either thrombin group （0.5 or 1.0u/ml） presents similar cell proliferation curves with two peaks, occurring at lh and at 24h. （2） Compared with Oh, the activity of Jak2 in thrombin group increased significantly at 6h（P〈0.05） and at 12h（P〈0.05）. Compared with thrombin group, AG490 decreased the thrombin-induced cells proliferations at 1h（P〈0.05） and at 24h（P〈0.05）. Conclusion （1） Cell proliferation induced by thrombin had two peaks at lh and 24h.This indicated that induction of thrombin was not only quickly and transient but also torpid and late. （2）The increase of Jak2 activity occurs before cell proliferation, which suggests that Jak2 is involved in signal transmission pathway of thrombin-induced cell proliferation.