细胞外调节激酶的表达及活化在不同年龄自发性高血压大鼠心肌肥厚中的作用

目的:研究不同年龄的自发性高血压大鼠(spontaneously hypertensive rat,SHR)心室肌组织中细胞外调节激酶(extracellular signal-regulated kinases,ERKs)的表达及活化与心肌肥厚的关系.方法:选择Wistar Kyoto(WKY)大鼠作对照,SHR和WKY大鼠按年龄分为5周、8周、14周和24周各4组,以左心室质量与体重的比值反映心肌肥厚的程度;采用Western blot方法测定大鼠左心室心肌组织中基础表达ERK (basal ERK,b-ERK)和磷酸化ERK(phosphorylated-ERK,p-ERK)的水平.结果:①与相同周龄WKY大鼠比较,SHR自8周龄起血压明显升高(P<0.001),14周后心肌肥厚指数明显增加(P<0.01).②各年龄组SHR与相同周龄WKY大鼠b-ERK水平比较均无明显差异(P>0.05). ③5周龄SHR p-ERK水平与同龄WKY大鼠无差异,8到24周SHR大鼠p-ERK水平明显高于同龄WKY大鼠(P<0.01).④心肌肥厚指数与b-ERK量无明显相关性,与p-ERK量呈正相关. 结论:在SHR大鼠心肌肥厚形成中,心肌组织b-ERK没有增加,p-ERK水平增高,ERK活性增加参与高血压心肌肥厚过程.

ERK expression and activation in myocardial hypertrophy of spontaneously hypertensive rats with different ages

Objective: To investigate the expression and activation of extracellular signal-regulated kinases(ERK) in myocardial hypertrophy of spontaneously hypertensive rats(SHR) with different ages.Methods: SHRs and Wistar Kyoto(WKY) rats were divided into 4 groups(5-,8-,14-,24-week old)respectively.The ratio of left ventricle weight to body weight(LVW/BW)was measured as the indicator of myocardial hypertrophy.The basal ERK expression(b-ERK) and phosphorylated-ERK(p-ERK) in myocardial tissue were examined by Western blot.Results: The blood pressure of SHR was significantly higher than that of age-matched WKY rats from 8(-week)-old(P<0.001).The ratio of LVW/BW in SHR was increased significantly from 14-week-old(P<0.01).There was no significant difference of b-ERK expression between SHR and age-matched WKY rats.The p-ERK level of 5-week-old SHR was similar to that of 5-week-old WKY rats.The p-ERK level of SHR was significantly higher than that of age-matched WKY rats from 8-week-old to 24-week-old(P<0.01).The ratio of LVW/BW was positively related to p-ERK level but not related to b-ERK.Conclusion: The activation of ERK may play an important role in the development of myocardial hypertrophy caused by hypertension.