CAJ | 학술논문

目的：探讨脑缺血及后适应对树鼩海马内质网应激信号分子蛋白激酶R样内质网激酶（ PERK）及葡萄糖调节蛋白78（GRP78）的影响及后适应的脑保护机制。方法：光化学反应诱导树鼩局部血栓性脑缺血，于脑缺血后3．5 h夹闭、打开缺血侧颈总动脉交替3个循环（每次5 min）以复制缺血后适应模型。 HE染色观察缺血侧海马神经元损伤及超微结构变化，RT－PCR检测脑缺血及后适应不同时间海马组织PERK及GRP78 mRNA表达的变化，免疫组织化学法与Western blot法检测PERK及GRP78的蛋白定位及表达变化。结果：海马神经元随脑缺血时间延长而损伤加重，缺血24 h损伤最为严重，后适应可减轻损伤。脑缺血4 h、24 h及72 h PERK的mRNA及蛋白表达较假手术组增高（P＜0．05），后适应组与相应的缺血组相比，PERK 的mRNA及蛋白表达减少，4 h、24 h差异显著（ P＜0．05）；脑缺血4 h、24 h及72 h GRP78的mRNA及蛋白表达与假手术组无明显差异，后适应24 h组较缺血24 h组表达增高（ P＜0．05）。结论：树鼩局部血栓性脑缺血可激活缺血侧海马内质网应激反应，引起PERK／eIF2α信号转导通路中相关分子PERK 的mRNA及蛋白表达增高。缺血后适应处理通过下调PERK、上调GRP78的表达，减轻内质网应激反应，减少神经元损伤，具有一定的脑保护作用。
목적：탐토뇌결혈급후괄응대수구해마내질망응격신호분자단백격매R양내질망격매（ PERK）급포도당조절단백78（GRP78）적영향급후괄응적뇌보호궤제。방법：광화학반응유도수구국부혈전성뇌결혈，우뇌결혈후3．5 h협폐、타개결혈측경총동맥교체3개순배（매차5 min）이복제결혈후괄응모형。 HE염색관찰결혈측해마신경원손상급초미결구변화，RT－PCR검측뇌결혈급후괄응불동시간해마조직PERK급GRP78 mRNA표체적변화，면역조직화학법여Western blot법검측PERK급GRP78적단백정위급표체변화。결과：해마신경원수뇌결혈시간연장이손상가중，결혈24 h손상최위엄중，후괄응가감경손상。뇌결혈4 h、24 h급72 h PERK적mRNA급단백표체교가수술조증고（P＜0．05），후괄응조여상응적결혈조상비，PERK 적mRNA급단백표체감소，4 h、24 h차이현저（ P＜0．05）；뇌결혈4 h、24 h급72 h GRP78적mRNA급단백표체여가수술조무명현차이，후괄응24 h조교결혈24 h조표체증고（ P＜0．05）。결론：수구국부혈전성뇌결혈가격활결혈측해마내질망응격반응，인기PERK／eIF2α신호전도통로중상관분자PERK 적mRNA급단백표체증고。결혈후괄응처리통과하조PERK、상조GRP78적표체，감경내질망응격반응，감소신경원손상，구유일정적뇌보호작용。
[ ABSTRACT] AIM:To investigate the effects of cerebral ischemia and postconditioning on protein kinase R-like endoplasmic reticulum kinase (PERK) and glucose-regulated protein 78 (GRP78) in the hippocampus tissue of tree shrew during endoplasmic reticulum stress and the mechanism of post-conditioning protecting the brain from damage.METH-ODS:The focal cerebral ischemic model was duplicated by photochemical reaction in tree shrew and the postconditioning was induced by alternatively occluding and opening the carotid artery of ischemic side for 3 cycles (5 min each cycle) at 3.5 h after ischemia.The damage and ultrastructural changes of the hippocampal neurons were observed by HE staining. The expression of PERK and GRP78 at mRNA and protein levels in the hippocampal tissue at different time points after cer-ebral ischemia and postconditioning was determined by RT-PCR, immunohistochemistry and Western blot.RESULTS:The injuries of hippocampal neurons were aggravated with prolonged cerebral ischemia, which was most severe at 24 h after ischemia while the postconditioning alleviated these damages correspondingly.The expression of PERK at mRNA and pro-tein levels was upregulated at 4 h, 24 h and 72 h after ischemia (P<0.05), while postconditioning downregulated the ex-pressions of PERK at ischemia and postconditioning 4 h (IP4 h) gruop and IP24 h group (P<0.05).The expression of GRP78 at mRNA and protein levels was not changed at 4 h, 24 h and 72 h after ischemia, while postconditioning upregu- <br> lated the expressions of GRP78 at IP24 h group (P<0.05).CONCLUSION:The focal thrombotic cerebral ischemia ac-tivates the endoplasmic reticulum stress in ischemic hippocampus of tree shrews, leading to the changes in mRNA and pro-tein expression of PERK in the PERK/eIF2αsignal transduction pathway.The postconditioning treatment alleviates endo-plasmic reticulum stress and neuronal damages by downregulating PERK and upregulating GRP78, thereby protecting the brain from injury.