阻断ERK信号通路降低大鼠脑创伤后MMP-9的表达及减轻脑水肿  

Blocking ERK signaling pathway lowers MMP-9 expression to alleviate brain edema after traumatic brain injury in rats

作　　者：唐兆华[1] 王文涛 刘自力[1] 孙晓川[1] 廖正步[1] 陈飞兰 蒋光远 霍钢[1] TANG Zhaohua;WANG Wentao;LIU Zili;SUN Xiaochuan;LIAO Zhengbu;CHEN Feilan;JIANG Guangyuan;HUO Gang(Department of Neurosurgery,First Affiliated Hospital of Chongqing Medical University,Chongqing,400016,China;Department of Neurosurgery,Affiliated Hospital of Northwest University,Xi'an,710018,China;Department of Neurosurgery,Chongqing Traditional Chinese Medicine Hospital,Chongqing 400021,China)

机构地区：[1]重庆医科大学附属第一医院神经外科,重庆400016 [2]西北大学附属医院神经外科,陕西西安710018 [3]重庆市中医院神经外科,重庆400021

出　　处：《南方医科大学学报》2020年第7期1018-1022,共5页Journal of Southern Medical University

基　　金：国家自然科学基金(81301630,81401070,81771355);国家临床重点专科建设财社(2011)170号;重庆市教委科学技术研究(KJ1500219);重庆市渝中区科技计划项目(20150108)。

摘　　要：目的观察并探讨阻断ERK通路激活对SD大鼠脑创伤后基质金属蛋白酶-9(MMP-9)表达变化及脑水肿形成的影响及意义。方法取健康成年雄性SD大鼠90只,随机分为:对照组:只在颅骨上做一直径约为4 mm的骨窗,不作脑创伤;脑创伤组:制作改进式Feeney’s创伤性脑损伤模型;ERK抑制组:脑创伤前15 min股静脉注射ERK抑制剂(SCH772984,500μg/kg),每组30只/组大鼠。制作改进式Feeney’s脑创伤模型后,分别在脑创伤后2 h、2 d时断头取脑,Evans Blue法测定血脑屏障通透性变化,干湿比重法测定脑组织含水量,RT-PCR法和Western blotting法检测各组大鼠脑组织ERK磷酸化的水平及MMP-9 mRNA及蛋白的表达水平。结果(1)与对照组比较,脑创伤组大鼠脑组织中ERK的磷酸化水平在伤后2 h和2 d均出现明显上升(P<0.01),MMP-9mRNA和蛋白的表达在脑创伤后2 d时表达也出现显著增高(均P<0.01);与脑创伤组比较,ERK抑制组大鼠脑组织中ERK的磷酸化水平在各时间点均明显下降(P<0.01),MMP-9 mRNA和蛋白在伤后2 d的过表达水平也较脑创伤组出现明显降低(均P<0.01);(2)脑创伤组大鼠的血脑屏障通透性较对照组在伤后出现显著升高(P<0.05),ERK抑制组大鼠的血脑屏障通透性则较脑创伤组出现明显降低(P<0.05);脑创伤组大鼠的脑含水量在伤后在2 d时出现显著增加(P<0.01),ERK抑制组大鼠的脑含水量则较脑创伤组有明显降低(P<0.01)。结论阻断ERK通路过度的活化可显著降低大鼠脑创伤后MMP-9高表达,减轻大鼠血脑屏障破坏及创伤性脑水肿,提示ERK信号通路在脑创伤后的过度活化可通过调节MMP-9的表达在创伤性脑水肿中发挥重要作用。Objective To investigate the effects of blocking the activation of ERK pathway on the expression of matrix metalloproteinase-9(MMP-9)and the formation of cerebral edema in SD rats after brain injury.Methods Ninety SD rats were randomly divided into 3 equal groups,including a sham-operated group,modified Feeney's traumatic brain injury model group,and ERK inhibition group where the ERK inhibitor SCH772984(500μg/kg)was injected via the femoral vein 15 min before brain trauma.At 2 h and 2 days after brain trauma,the permeability of blood-brain barrier was assessed by Evans blue method,the water content of the brain tissue was determined,and the phosphorylation level of ERK and the expression level of MMP-9 mRNA and protein were measured by RT-PCR and Western blotting.Results Compared with the sham-operated group,the rats with brain trauma exhibited significantly increased level of ERK phosphorylation at 2 h and significantly increased expression of MMP-9 mRNA and protein 2 days after the injury(P<0.01).Treatment with the ERK inhibitor significantly decreased the phosphorylation level of ERK after the injury(P<0.01),suppressed over-expression of MMP-9 mRNA and protein 2 days after the injury(P<0.01).The permeability of blood-brain barrier increased significantly 2 h after brain trauma(P<0.05)and increased further at 2 days(P<0.01);the water content of the brain did not change significantly at 2 h(P>0.05)but increased significantly 2 d after the injury(P<0.01).Treatment with the ERK inhibitor significantly lowered the permeability of blood-brain barrier and brain water content after brain trauma(P<0.01).Conclusion Blocking the activation of ERK pathway significantly reduced the over-expression of MMP-9 and alleviates the damage of blood-brain barrier and traumatic brain edema,suggesting that ERK signaling pathway plays an important role in traumatic brain edema by regulating the expression of MMP-9.

关 键 词：ERK 基质金属蛋自酶9 脑水肿 创伤性脑损伤 

分 类 号：R651.15[医药卫生—外科学]