细胞外信号调节激酶信号通路对癫痫大鼠海马内HIF—1α表达的调控作用

Regulation of ERK signaling pathway in HIF-1α expression in the hippocampus of epileptic rats

目的探讨细胞外信号调节激酶（ERK）信号通路是否参与调节癫痫大鼠海马内低氧诱导因子．1a（HIF．1d）的表达。方法208只21d龄SD大鼠按随机数字表法分为癫痫持续状态（SE）组（96只）、对照组（96只）和PD98059组（16只），SE组腹腔注射戊四氮（PTZ）溶液制作SE模型，对照组注射等剂量生理盐水，造模后0．5、1、1．5、6、12、24h采用RT—PCR、Westem blotting分别检测2组大鼠海马内HIF-1α、ERKl／2mRNA和蛋白的表达；PD98059组大鼠腹腔注射PD98059，10min后腹腔注射PTZ溶液制作SE模型，造模成功后1h采用RT—PCR检测大鼠海马内HIF-1α、ERK1／2mRNA的表达，造模成功后1．5h采用Western blotting检测其相应蛋白的表达。结果与对照组比较，SE组大鼠海马内HIF-1α、ERK1／2mRNA及其蛋白的表达明显升高．差异均有统计学意义（P〈0．05）；其中ERK1／2mRNA的表达高峰（1．112±0．126）在SE后1h，蛋白的表达高峰（1．127±0．155）在SE后1．5h；而HIF-1α mRNA的表达高峰f0．589±0．090）在SE后1．5h，蛋白的表达高峰（0．230±0．052）在SE后6h。与SE组相比，PD98059组大鼠海马内HIF-1α mRNA、ERK1／2mRNA和蛋白的表达均降低，差异均有统计学意义（P〈0．05）。SE组大鼠中，T-ERK1／2与HIF-1α mRNA的表达呈正相关（r=0．688，P=0．000）。结论戊四氮诱导发育期大鼠SE后ERK信号通路被激活，参与了海马内HIF-1α的表达调控。

Objective To explore whether extracellular signal-reg-ulated kinase （ERK） signaling pathway is involved in the hypoxia-inducible factor-1α （HIF-1α expression in the hippocampus of epileptic rats. Methods A total of 208 21-d old SD rats were equally randomized into status epilepticusgroup （SE, n=96）, normal controlgroup （NS, n=96） and PD98059 （the ERKsignaling pathway specific inhibitor） treatment group （n=16）, respectively; SE rat models of the SE group were induced by intraperitoneal injection of 1% PTZ （80 mg/kg）, and rats of the NS group received injection of normal saline （NS）; 0.5, 1, 1.5, 6, 12 and 24 h after the inducement, the mRNA and protein expressions of HIF-1α and ERK1/2 in the hippocampus of rats in these two groups were examined by RT-PCR and Western blotting. For rats in the PD98059 treatment group, PD98059 was intraperitoneally injected 10 minutes before intraperitoneal injection of pentylenetetrazol; 1 h after the inducement, the mRNA expressions of HIF-1α and ERK1/2 in the hippocampus of rats were examined by RT-PCR, while 1.5 h after the inducement, the protein expressions of HIF-1α and ERK1/2 in the hippocampus of rats were examined by Western blotting. The results of the PD98059 treatment group would be compared with those of the SE group. Results Compared with the NS group, the mRNA and protein expressions of H1F-1α and ERK1/2 in the hippocampus of rats in the SE group after SE increased significantly; the peak expression time ofERK1/2 mRNA was 1 h after SE （1.112±0.126 h）, and the ERK1/2 protein mostly expressed at 1.5 h after SE （1.127±0.155 h）. As to HIF-la mRNA and its protein, the peak expression time was 1.5 h after SE （0.589±0.090 h） and 6 h after SE （0.230±0.052 h）, respectively （P〈0.05）. Compared with the SE group, the mRNA and protein expressions of HIF-ltx and ERK1/2 in the hippocampus of all the rats in the PD98059 treatment group after SE decreased significantly （P〈0.05）; positive correlation between HIF-1α and ERK1/2 mRNA in the SE group was noted （r=0.688 ,P=-0.000）. Conclusion ERK signaling pathway is activated in the epileptic rats and it participates in the expression of HIF- 1 α in the hippocampus.