细胞外信号蛋白调节激酶5在异氟醚后处理减轻大鼠海马脑片缺氧无糖损伤中的作用

Involvement of ERK5 in Isoflurane posttreatment-mediated protective effect on hippocampal oxygen-glucose deprivation injury in rats

摘要:

目的探讨异氟醚后处理大鼠海马脑片缺氧无糖（OGD）损伤神经保护机制中细胞外信号蛋白调节激酶5（ERK5）的作用。方法使用雄性SD 大鼠，将其麻醉后取出海马组织，制成离体脑片，然后随机进行正常对照组（Con 组）、损伤组（OGD 组）和药物处理组的处理。采用花粉活力染色（TTC）法评价各组脑片损伤程度，采用碘化丙啶（PI）染色法检测海马CA1 区神经细胞凋亡程度，采用实时荧光定量聚合酶链反应（qRT-PCR）测定细胞外调节蛋白激酶信使核糖核酸（ERK5 mRNA）的表达，采用Western blot 法检测ERK5蛋白的表达与磷酸化水平。结果与Con组比较，OGD组脑片损伤程度升高、海马CA1区凋亡细胞增多，海马组织内ERK5 mRNA和p-ERK5表达升高（p <0.05）；XMD组阻断ERK5 mRNA和p-ERK5表达，脑片损伤程度升高、海马CA1区凋亡细胞增多（p <0.05）。与OGD、1.5%ISPOC和4.5%ISPOC组比较，3.0% ISPOC 组脑片损伤程度减轻、海马CA1 区凋亡细胞减少，海马组织内ERK5 mRNA和p-ERK5表达升高（p <0.05）。与3.0%ISPOC组比较，XMD阻断ISPOC海马组织内ERK5 mRNA 和p-ERK5 表达，脑片损伤程度升高、海马CA1 区凋亡细胞增多（p <0.05）。结论一定浓度的异氟醚后处理大鼠海马脑片对抗OGD损伤的保护性机制可能与上调ERK5 mRNA和ERK5 磷酸化水平有关。

关键词:麻醉药;异氟醚后处理;细胞外信号调节MAP激酶类;脑缺血;海马

Abstract:

Objective To investigate the role of extracellular signal-regulated protein kinase 5 (ERK5) on Isoflurane posttreatment-mediated decrease of hippocampal injury in rat models of oxygen-glucose deprivation (OGD). Methods Male SD rats were randomly divided into four groups: the normal control (Con) group, the OGD group, the XMD group, and the ISPOC group. Rats were anesthetized followed by harvest of the hippocampus for further preparation of tissue slices. Histological analysis of hippocampus was achieved by 2% 2, 3, 5 -triphenyltetrazolium chloride (TTC) staining. Neuronal apoptosis in hippocampus CA1 region was analyzed by propidium iodide (PI) fluorescence staining. The expression level of ERK5 mRNA was determined by real-time fluorescent PCR. The ERK5 protein expression and phosphorylation were detected by Western blot. Results Compared with the Con group, the degree of hippocampal injury, apoptosis rate in hippocampal CA1 region and the expression levels of ERK5 mRNA and p -ERK5 in the OGD group were increased significantly (p < 0.05). In the XMD group, the expression levels of ERK5 mRNA and p -ERK5 were decreased, and the degree of tissue injury and the apoptosis rate in hippocampal CA1 region increased (p <0.05). Compared with the group 3.0% ISPOC, XMD8-92 independently diminished the expression of ERK5 mRNA and phosphorylation of ERK5 in the hippocampus, and enhanced tissue injury as well as apoptosis rate in the XMD+ISPOC group (p < 0.05). Conclusions The protective effect of Isoflurane posttreatment on hippocampal OGD injury in rats may be related to the upregulation of ERK5 mRNA and phosphorylation of ERK5.

Key words:anesthetics; Isoflurane posttreatment; extracellular signal-regulated MAP kinases; brain ischemia;hippocampus