乌司他丁对大鼠脑缺血再灌注后大脑皮质内质网应激相关分子表达的影响

摘要

目的：观察乌司他丁对大鼠脑缺血再灌注后大脑皮质内质网应激（ endoplasmic reticulum stress ， ERS）相关分子表达的影响。方法健康SD大鼠90只，随机分为3组，假手术组（S组，n＝30），脑缺血再灌注组（I／R组，n＝30），乌司他丁处理组（U组，n＝30）。采用线栓法制备大脑中动脉缺血再灌注模型，缺血2 h，再灌注24 h。HE染色观察大鼠脑组织病理改变，神经功能缺陷评分评价脑损伤程度，2，3，5－氯化三苯基四氮唑（ TTC）染色法检测脑梗死体积，末端标记法（ TUNEL ）法检测细胞凋亡；采用western blot 法检测缺血侧大脑皮层 GRP78、CHOP、caspase－12蛋白表达情况。结果与S组比较，I／R组和U组大鼠脑缺血再灌注后的神经功能学评分（ NDS）升高（P＜0.05），脑梗死体积增大（P＜0.05），细胞凋亡数明显增加（P＜0.05），I／R组和U组再灌注24h缺血侧大脑皮质GRP78、CHOP和caspase－12蛋白均表达上调（ P＜0.05）；与I／R组比较，U组大鼠脑缺血再灌注后的神经功能缺损明显改善（P＜0.05），脑梗死体积减少（P＜0.05），细胞凋亡数明显减少（P＜0.05）；U组缺血侧大脑皮质GRP78表达上调幅度明显大于I／R组、CHOP和caspase－12蛋白表达上调幅度明显小于I／R组（ P＜0.05）。结论乌司他丁可明显减轻大鼠脑缺血再灌注损伤，其机制可能与增加GRP78蛋白表达、拮抗CHOP和caspase－12蛋白表达，阻断内质网应激（ ERS）启动的凋亡通路有关。%Objective To investigate the protective effects of ulinastatin on express of GRP 78、CHOP and caspase-12, the molecules related to endoplasmic reticulum stress (ERS),after ischemia reperfusion injury in rats.Methods Ninety rats were equally randomized into 3 groups(n=30): Sham group (S group,n=30), Ischemia -reperfusion group (I/R group, n=30), Ulinastatin group (U group, n=30).Focal transient cerebral ischemia model was established with intralu-minal occlusion fo left meddle cerebral artery .Made through 2 hours of temporary middle cerebral artery occlusion , followed with 24 hours of reperfusion .The pathological results were investigated by HE staining and the cerebral injury situation was e -valuated by neurological deficit scores .Infract volume was measured by TTC staining , apoptosis was detected by TdT -medi-ated dUTP and nick end labeling (TUNEL), and expression of GRP78, CHOP and caspase -12 were meastured by western blot.Results Compared with the S group , the number of apoptotic cells were significantly increase in I /R group and U group (P<0.05);infarct volume and expression of GRP -78, CHOP and caspase-12 were significantly increased in I/R group and U group (P<0.05).The infarct volume and the number of apoptotic cells were significantly less in U group than in I/R group ( P<0.05 ) .GRP78 expression was higher in U group than in I/R group ( P<0.05 ) , however CHOP and caspase-12 expression was less in U group than in I/R group (P<0.05).Conclusion Ulinastatin has a protective effect on cerebral ischemia reperfusion injury , which may related to increased GRP 78, decreased CHOP and caspase -12 expres-sion and to inhibition of the ERS -induced apoptosis pathway .