血浆游离mtDNA及脑组织TLR-9/MAPK的表达在蛛网膜下腔出血中的意义

【摘要】 目的 探讨蛛网膜下腔出血（SAH）模型大鼠血浆中游离线粒体DNA（mtDNA）的水平及脑组织中Toll样受体-9/丝裂原蛋白激酶（TLR-9/MAPK）的表达及意义。方法 将40只大鼠随机分为SAH组和假手术(Sham)组，每组20只。SAH组采用血管内穿刺法建立SD大鼠SAH动物模型，Sham组仅穿刺但不造成蛛网膜下腔出血。模型建立成功24 h后，采用荧光定量实时PCR检测大鼠外周血中血浆游离mtDNA的表达量；采用逆转录PCR（RT-PCR）和免疫组化法分别检测大鼠脑组织中TLR-9、P38 MAPK的表达。结果 SAH组大鼠在建模24 h后血浆中游离mtDNA表达量高于Sham组（P <0.05）；RT-PCR及免疫组化检测均显示脑组织中TLR9、P38 MAPK表达较Sham组增多（P <0.05）。 结论 血浆游离mtDNA与脑组织中 TLR-9/MAPK的表达存在协同升高的现象，mtDNA可能通过TLR-9/MAPK通路介导脑组织局部及全身性炎症反应的发生。
【Abstract】 Objective To determine the plasma level of mitochondrial DNA (mtDNA) and the expression of Toll like receptor-9/mitogen-activated protein kinase (TLR-9/MAPK) in the brain tissues of rats with subarachnoid hemorrhage (SAH). Methods Sprague-Dawley rats were used to establish SAH models with a modified method of endovascular perforation. Twenty four hours after the establishment of the models, the plasma level of mtDNA in the rats was detected by real-time PCR; the expressions of TLR-9 and P38 MAPK in the brain tissues were detected by reverse transcription PCR (RT-PCR) and immunohistochemical staining. Differences between the SAH (n =20) and sham-surgical (n =20) groups were compared. Results Rats in the SAH group had higher levels of plasma mtNDA and expressions of TLR-9 and P38 MAPK in brain tissues than those in the sham-surgical group (P <0.05). Conclusion Plasma free mtDNA and expressions of TLR-9/MAPK increase simultaneously in rats with SAH. mtDNA may induce system and local inflammation reactions in brain.