OX-LDL及辛伐他汀对平滑肌细胞PKC活性和胞内Ca^(2+)的影响

Effect of OX-LDL and simvastatin on PKC activity and cytosolic free Ca^(2+) in cultured rat aortic smooth muscle cells

目的 :探讨OX -LDL是否对大鼠主动脉平滑肌细胞 (ASMC)蛋白激酶C(PKC)活性和胞浆内游离钙([Ca2 + ]i)水平有影响。方法 :应用γ - [3 2 P]-ATP磷酸转移法和Fluo - 3/Am荧光负载、流式细胞术分别检测PKC活性和胞内 [Ca2 + ]i)水平。结果 :OX -LDL呈剂量依赖方式促进ASMCPKC总活性增加 ,并可引起ASMC中PKC发生浆膜的转移。胞浆内 [Ca2 + ]i以 2个时相升高 ,即快速相和持续相。而辛伐他汀能明显抑制OX -LDL引起的ASMC中PKC活性的浆膜转移 ,并显著降低持续相胞浆内钙水平 ,而对快速相无影响。结论 :OX -LDL能引起ASMC内信号通路PKC及 [Ca2 + ]i的动态变化 ,二者密切相关。

AMI: To clarify whether OX-LDL and simvastatin can induce the changes of PKC activity and cytosolic free Ca 2+ in rat aortic smooth muscle cells (ASMC). METHODS: PKC activity and cytosolic free Ca 2+ were measured by its ability to transfer phosphate from ATP to lysine-rich histone and flow cytometric analysis after loading with the Ca 2+ dye fluo 3/Am, respectively. RESULTS: OX-LDL increased PKC total activity in a dose-dependent manner and induced translocation of PKC from the cytosolic to membrane, while OX-LDL induced biphasic [Ca 2+ ]i responses including the rapid initial transient phase and the sustained phase. When simvastatin was added, the translocation of PKC was markedly decreased and simvastatin did not impair the initial peak response to OX-LDL but significantly reduced the subsequent plateau phase. CONCLUSSION: OX-LDL can induce dynamic changes of signal transduction of PKC and cytosolic free Ca 2+ in ASMC and these two events are closely linked.