摘要
目的 :探讨蛋白激酶C(PKC)和细胞外信号调节激酶 (ERK)在大鼠缺氧预处理 (APC)延迟保护机制中的作用及二者之间的相互关系。方法 :建立培养乳鼠心肌细胞缺氧 /复氧 (A/R)损伤和APC延迟心肌保护模型 ,用PKC兴奋剂 (PMA)模拟预处理延迟保护模型 ,分别应用PKC和ERK抑制剂干预模型 ,并在各组相当于预处理后 10min取材检测ERK活性。以实验终点检测培养基中乳酸脱氢酶 (LDH)活性、细胞存活率、心肌细胞超氧化物歧化酶(SOD)活性和丙二醛 (MDA)含量作为心肌细胞损伤的指标。结果 :预处理组心肌细胞存活率和SOD含量均显著高于A/R组 (P <0 0 5 ) ,培养液内LDH漏出和心肌细胞内MDA含量显著低于A/R组 (P <0 0 5 ) ,ERK活性显著高于A/R组 (P <0 0 5 ) ,应用PMA激活PKC可以模拟预处理的保护作用 ;ERK阻滞剂PD980 5 9消除了缺氧和PMA的预处理保护作用 ,并抑制了预处理后的ERK活性的升高 ;PKC抑制剂多粘菌素B对APC引起的ERK激活及延迟保护作用无明显影响 ,但可抑制PMA诱导的保护现象。结论 :ERK活化可能是APC延迟保护机制中的必须信号转导途径 ;PKC活化可以通过激活ERK启动缺氧预处理的延迟保护机制。
AIM: To investigate the roles of protein kinase C (PKC) and extracellular signal-regulated kinase (ERK) in delayed protection mechanism of anoxia preconditioning (APC) in rat cardiomyocytes.METHODS: The anoxia/reoxygention (A/R) injury, APC and PMA (an activator of PKC) preconditioning models were established in cultured neonatal rat cardiomyocytes and the effects of PKC and ERK blokers on the models were observed. ERK activity was assayed at 10 min after preconditioning in every group. The cellular MDA, SOD, cell viability and LDH release were measured at the end of the study. RESULTS: Compared with the cardiomyocyte in A/R group, the percentage of viable cells and SOD activity were greatly increased (P<0.05), the cellular MDA and LDH leakage were decreased in PMA, APC, APC+polymyxin B (a PKC bloker) groups (all P<0.05). Significant ERK activation was achieved through exposure of neonatal cardiomyocytes to PMA or APC. PD98059 (an ERK bloker) completely removed all the protection and prevented ERK activation induced by PMA or APC. Polymyxin B abolished ERK activation and cardiomyocyte protection in PMA but not in anoxia preconditioning. CONCLUSION: ERK might be a major cellular signal molecule in the mechanism of APC. PKC may play a role by ERK activation in the mechanism, but there might be another way to activate ERK in the mechanism that is not related to the PKC activation.
出处
《中国病理生理杂志》
CAS
CSCD
北大核心
2003年第4期503-506,共4页
Chinese Journal of Pathophysiology
基金
辽宁省科委资助项目 (No.9710 6 2 )
