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

Plasma Free mtDNA and Expression of TLR-9/MAPK in Brain Tissues of Rats with Subarachnoid Hemorrhage

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24h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24h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。

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.