低频脉冲电场对PC12细胞酪氨酸羟化酶和多巴胺合成的影响

运用Western印迹和HPLC分别测定不同时间电场刺激和刺激后不同培养时间条件下,PC12细胞内酪氨酸羟化酶(TH)和细胞培养液中多巴胺(DA)含量的变化。结果显示,受到短时间(5、10min)脉冲电场刺激的PC12细胞,经较短时间(2天)的培养后,细胞内TH的含量和培养液中DA的含量均比对照组有所提高,但随着培养时间的延长(3~5天),TH和DA的含量均明显下降。然而,长时间(15、20、30min)脉冲电场刺激组则先表现为TH和DA的合成受到抑制,但随着培养时间的延长,其合成则被逐渐激活。采用蛋白激酶A(PKA)特异性抑制剂H-89和有丝分裂原活化蛋白激酶的激酶(MEK1/2)特异性抑制剂U0126,研究脉冲电场刺激所激活的与TH和DA合成相关的信号通路。结果表明,在没有神经生长因子(NGF)存在的情况下,PC12细胞主要通过PKA通路来激活TH的合成,低频脉冲电场刺激也主要激活PKA通路,因为抑制这条信号通路能显著抑制电场刺激所诱导的TH合成。

The Effects of Low-frequency Pulsed Electrical Field on the Synthesis of Tyrosine Hydroxylase and Dopamine in PC12 Cells

The effects of low frequency pulsed electric field (LF-PEF) on the synthesis of tyrosine hydroxylase (TH) and dopamine (DA) were studied by Western blotting and HPLC. The results showed that short exposure to low-frequency pulsed electrical field (LF-PEF) (5, 10 min) could significantly activate the express of TH and DA after short culture period (2 days). The synthesis of TH and DA was inhibited in the longer exposed groups (15, 20, 30 min) within the same short culture period. After a long culture period, the synthesis of TH and DA was inhibited in the short exposed groups, while enhanced in longer exposed groups. The related signal pathways were tested by special inhibitor of protein kinase A (PKA) (H-89) and special inhibitor of mitogen activated protein-kinase kinase (MEK1/2) (U0126). The results suggested that PKA pathway was the most important pathway in-volved in the normal TH synthesis and the LF-PEF stimulated TH synthesis because H-89 could totally inhibit the synthesis of TH induced by LF-PEF.