丝裂素活化蛋白激酶的激活和转核与大鼠 血管平滑肌细胞增殖关系的研究

目的 探讨丝裂素活化蛋白激酶（MAPK）激活、转核与血管紧张素Ⅱ（AngⅡ)刺激血管平滑肌细胞（VSMC）增殖间的关系。方法 本实验采用培养大鼠胸主动脉VSMC。用^3H-胸腺嘧啶核苷（^3H-TdR)掺入法测定DNA合成，用p43/p44磷酸化抗MAPK抗体的蛋白免疫印迹法测定MAPK蛋白量，用免疫细胞化学技术观察MAPK活化并转位入细胞核的过程。结果 （1）AngⅡt和PD98059的上述作用都呈剂量依赖性。（2）AngⅡ对MAPK蛋白表达有显著增强作用。此作用同样被PD98059以剂量依赖方式抑制。（3）AngⅡ刺激5min后，MAPK出现在VSMC的细胞浆中，30min时MAPK进入细胞核，3h后MAPK染色从核内消失，上述MAPK转核过程被PD98059抑制。结论 本实验证实人细胞核，3h后MAPK染色从核人消失，上述MAPK转核过程被PD98059抑制。结论 本实验证实AngⅡ能激活培养大鼠主动脉VSMC的MAPK，活化的MAPK从细胞浆转位进入细胞核导致VSMC增殖。

The activation and translocation of mitogen-activated protein kinase and the proliferation of vascular smooth muscle cell in rat

Objective To investigate the activation and translocation ofmitogen-activated protein kinase (MAPK) in the proliferation of vascular smooth muscle cell (VSMC) induced by angiotensin II (AngII). Methods Cultured VSMCs were obtained from rat thoracic aorta. DNA synthesis was determined by measuring the incorporation of 3H-thymidine into cells. The MAPK activity was evaluated by an immunobloting technique using anti-p42/p44 phospho-MAPK antibody and the presence of MAPK in the cytoplasm or nuclear was confirmed by immunocytochemistry using the specific antibody. Results (1) Ang II (10-8－10-6 mol/L) dose-dependently increased the incorporation of 3H-thymidine into VSMC, the increase in DNA synthesis by Ang II(10-6 mol/L) was inhibited by PD98059 (1-50 μmol/L), a specific MAPK kinase antagonist, in a dose-dependently manner. (2) The p42-p44 MAPK activities were significantly enhanced by Ang II, the activation could be also dose-dependently inhibited by PD98059 (1-50 μmol/L). （3） The activated 42/p44 MAPK appeared in cytoplasm at 5 min, then translocated to nucleus at 30 min and finally disappeared from the nucleus at 3h after the stimulation of AngII. The translocation process of MAPK induced by 10-6 mol/L AngII was blocked distinctly by PD98059 (50 μmol/L). Conclusion The results indicated that MAPK might be involved in cell proliferation of rat VSMC induced by Ang II through its activation, then translocation to nucleus.