ERK1／2信号转导通路在七氟醚后处理减轻大鼠海马脑片缺氧无糖损伤中的作用

Role of ERK1/2 signal transduction pathway in sevoflurane postconditioning-induced reduction of oxygenglucose deprivation injury in rat hippocampal slices

目的评价细胞外信号调节激酶1／2（ERKI／2）信号转导通路在七氟醚后处理减轻大鼠海马脑片缺氧无糖损伤中的作用。方法选取符合标准的大鼠海马脑片，采用随机数字表法，将其随机分为5组（n=10）：缺氧无糖组（OGD组）海马脑片进行15min缺氧无糖处理，即将灌流液改为经95％N2-5％CO2混合气体饱和的无糖人工脑脊液（aCSF）；4％七氟醚后处理组（Sevo组）缺氧无糖处理后用4％七氟醚平衡后的aCSF灌流30min；ERK1／2特异性抑制剂PD98059组（PD组）缺氧无糖处理后用含ERK1／2特异性抑制剂PD98059（50μmol／L）的aCSF灌流10min；二甲基亚砜组（DMSO组）缺氧无糖处理后用含1mol／LDMSO的aCSF灌流10rain；4％七氟醚后处理＋PD98059组（SPD组）缺氧无糖处理后用含ERKI／2特异性抑制剂PD98059（50μmol／L）并通入4％七氟醚的aCSF灌流30min，处理完成后各组均再用正常aCSF灌流1h。采用脑片灌流及电生理技术，细胞外记录海马CAl区的顺向群峰电位（OPS）；采用Trc染色．定量比色法评价海马脑片损伤程度。结果与OGD组比较，Sevo组OPS恢复程度和恢复率升高，海马脑片损伤程度降低（P〈0．01），其余3组各指标差异无统计学意义（P〉0．05）；与Sevo组比较，PD组、DMSO组和SPD组OPS恢复程度和恢复率降低，海马脑片损伤程度升高（P〈0．01）。结论ERK1／2信号转导通路参与了七氟醚后处理减轻大鼠海马脑片缺氧无糖损伤的过程。

Objective To evaluate the role of ERK1/2 signal transduction pathway in sevoflurane postconditioning-induced reduction of oxygen-glucose deprivation （OGD） injury in rat hippocampal slices. Methods Male adult SD rats weighing 80-100 g were anesthetized with ether and decapitated. The hippocampi were removed and sagittally sliced （400 μm thick） and placed in artificial cerebrospinal fluid （aCSF） aerated with 95% 02-5% CO2 . Fifty hippocampal slices were randomly divided into 5 groups （ n = 10 each） ： OGD group; 4% sevoflurane postconditioning group （group Sevo） ; PD98059 （specific inhibitor of ERK） group （group PD） ; dimethyl sulfoxide （DMSO） group; 4% sevoflurane postconditioning ＋ PD98059 group （group SPD）. OGD was induced by incubating the slices in glucose-free aCSF aerated with 95% N：- 5% CO2 for 15 min in group OGD. The hippocampal slices were perfused with aCSF saturated with 4% sevoflurane for 30 min after OGD was induced in group Sevo. The hippocampal slices were perfused with aCSF containing PD98059 50μmol/L for 10 min after OGD was induced in group PD. The hippocampal slices were perfused with aCSF containing DMSO 1 mol/L for 10 min after OGD was induced in group DMSO. The hippocampal slices were perfused with aCSF containing PD98059 50μmol/L and aerated with 4 % sevofiurane for 30 min after OGD was induced in group SPD. The hippocampal slices were then perfused with plain aCSF for 1 h again in all the groups. The electrophysiologicaI technique was used to record the amplitude of orthodromic population spike （OPS） in the stratum pyramidale of the CAI region. TTC staining was used to determine the degree of tissue injury. Results Compared with group OGD, the recovery amplitude and rate of OPS were significantly increased, and the degree of tissue injury was significantly decreased in group Sevo （ P 〈 0.01 ）, while no significant change was found in each parameter in the other three groups （P 〉 0.05）. Compared with group Sevo, the recovery amplitude and rate of OPS were significantly decreased, and the degree of tissue injury was significantly increased in groups PD, DMSO and SPD （ P 〈 0.01 ）. Conclusion ERK1/2 signal transduction pathway is involved in sevoflurane postconditioning-induced reduction of OGD injury in rat hippocampal slices.