MEK抑制剂阻断小鼠脑缺血后ERK通路的激活和IL-1β mRNA合成

MEK Inhibitor Prevents ERK Cascade Activation and IL-1β mRNA Production after Cerebral Ischemia in Mice

目的 研究细胞外信号调节激酶 (ERKs)在脑缺血中的作用以及U0 12 6对缺血脑组织保护作用的机制。方法 线栓法制作小鼠大脑中动脉栓塞 (MCAO)模型 ,颈内静脉注射U0 12 6 ;Westernblot法和免疫组化法检测 pMEK、pERK1/2和 pElk 1;核糖核酸酶保护测定法检测IL 1βmRNA含量。 结果 注射U0 12 6后的MCAO小鼠 pMEK活性降低 ,其降低幅度与U0 12 6有剂量依赖的关系 ,并在缺血前给药有效 ;U0 12 6注射后pERK1/2和 pElk 1也表现出相似的下降变化。小鼠MCAO后 1到 2hIL 1βmRNA水平上升 ;而注射U0 12 6后IL 1βmRNA在MCAO后 1至 4h内下降。 结论 ERK在小鼠脑缺血中发挥重要作用。静脉注射MEK抑制剂U0 12 6可阻断脑缺血引起的pMEK、pERK1/2和 pElk 1的活性增加。U0 12 6通过阻断ERK通路进而降低IL

Purpose: To study the role of extracellular signal regulated kinases (ERKs) in cerebral ischemia and the mechanism of protective effects of U0126 on ischemic brain. Methods: Mice underwent left middle cerebral artery occlusion (MCAO) by introducing a suture in the lumen. U0126 was injected intravenously through the internal jugular vein. Phosphorylated MEK (pMEK), phosphorylated ERK1/2 (pERK1/2), and phosphorylated Elk-1(pElk-1) was determined by Western blot analysis of immunohistochemistry. Interleukin (IL)-1β mRNA level was measured by ribonuclease protection assay. Results: pMEK was reduced in ischemic mice after U0126 injection. The reduction was dose dependent and treatment time related. pERK1/2 and pElk-1 were also reduced in a similar pattern. IL-1β mRNA increased during 1 to 2 h of MCAO. After injection of U0126, it was down-regulated during 1 to 4 h of MCAO. Conclusions: ERK cascade plays a critical role in cerebral ischemia. The protective effect of U0126 against ischemic injury is probably achieved by reduction of IL-1β mRNA via the inhibition of ERK pathway.