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 |
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引用本文: | 唐兆华,王文涛,刘自力,孙晓川,廖正步,陈飞兰,蒋光远,霍 钢.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[J].南方医科大学学报,2020,40(7):1018-1022. |
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作者姓名: | 唐兆华 王文涛 刘自力 孙晓川 廖正步 陈飞兰 蒋光远 霍 钢 |
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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(SCH772984,500 μg/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。
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关 键 词: | ERK 基质金属蛋自酶9 脑水肿 创伤性脑损伤 |
Blocking ERK signaling pathway lowers MMP-9 expression to alleviate brain edema
after traumatic brain injury in rats |
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Abstract: | 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 (500 μg/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. |
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Keywords: | ERK matrix metalloproteinase-9 brain edema traumatic brain injury |
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