肿瘤抑制因子PTEN与心肌肥大关系的研究

目的 观察肿瘤抑制因子PTEN在心肌肥厚大鼠心肌组织以及在血管紧张素Ⅱ诱导的肥大心肌细胞中的表达,探讨PTEN在心肌肥大发生发展中的作用以及相关机制。方法采用腹主动脉狭窄术制备压力超负荷心肌肥厚动物模型,及血管紧张素Ⅱ诱导新生大鼠心肌细胞肥大模型,应用逆转录-聚合酶链式反应(RT-PCR)方法、Western blot及免疫组化等方法,分别检测各组PTEN mRNA和蛋白表达的变化,以及PTEN蛋白在心肌细胞中的定位。结果(1)与对照组相比,心肌肥厚组大鼠左室肌PTEN mRNA和蛋白表达均明显减少;血管紧张素Ⅱ诱导心肌细胞肥大组PTEN蛋白表达明显减少。(2)与心肌肥厚组相比,卡托普利组大鼠左室心肌PTEN mRNA和蛋白表达增加,接近对照组。(3)免疫组化实验结果显示心肌细胞胞核内有阳性免疫产物生成,提示PTEN蛋白定位于心肌细胞核内。结论PTEN在心肌肥大发生发展中可能起负调控作用,该作用与肾素-血管紧张素系统密切相关。

Expression of tumor suppressor PTEN in hypertrophy cardiomyocyte

OBJECTIVE: To investigate the role of tumor suppressor PTEN in cardiac hypertrophy, the expression of PTEN mRNA and protein was analyzed in the tissue of left ventricle in abdominal aorta constricted-induced cardiac hypertrophic rats which treated with and without captopril. The expression of PTEN mRNA and protein in cultured neonatal rat cardiomyocyte treated with AngII was studied. METHODS: SD rats were divided into control group, hypertrophy group and captopril group. The expression of PTEN in different groups at 2 and 4 weeks after operation as well as in cultured neonatal rat cardiomyocyte treated with AngII was detected by RT-PCR and Western blot. The localization of PTEN in left ventricle and cultured cardiomyocyte was determined by immunohistochemistry. RESULTS: (1) Compared with control group, the expressions of PTEN mRNA and protein in left ventricle of hypertrophy group as well as in cultured cardiomyocyte treated with AngII were reduced. (2) Compared with hypertrophy group, the expressions of PTEN mRNA and protein in left ventricle of captopril group were upregulated, which were similar to those of control group. (3) Positive immunohistochemical staining of PTEN was located in the nucleus of cardiomyocytes. CONCLUSION: PTEN may play a negative regulation role in the process of cardiac hypertrophy, and the role of PTEN may be closely related with renin-angiotesin system.