摘要
目的心血管外科手术的脑保护问题成为近年来的研究热点。文中观察缺血后处理对深低温停循环(deep hypothermic circulatory arrest,DHCA)大鼠脑组织的保护作用,探讨其脑保护作用的机制。方法健康雄性清洁级SD大鼠36只,随机分为3组:假手术组、DHCA组、缺血后处理组。采用改良的四血管法制作DHCA大鼠脑保护模型。假手术组:只暴露而不电凝及夹闭血管。DHCA组:造模成功后,阻断45 min,开放后不做任何处理。缺血后处理组:建立DHCA模型,在开放时反复进行3个循环的开放15s/阻断15s,然后全面开放。再灌注24h,在各组中分别随机取8只大鼠,制作脑组织匀浆,检测其肿瘤坏死因子α(TNF-α)、白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)及超氧化物歧化酶(superoxide dismutase,SOD)活性及丙二醛(malondialdehyde,MDA)含量;各组中余下的4只大鼠,制作脑组织病理切片,光镜及透射电镜观察脑海马组织常规病理及超微结构变化;TUNEL法检测海马神经细胞的凋亡。结果 DHCA组、缺血后处理组与假手术组相比,炎性因子TNF-α、IL-1、IL-6明显升高,SOD活性明显降低,MDA含量明显增加;而缺血后处理组与DHCA组相比,炎性因子TNF-α、IL-1、IL-6明显降低,SOD活性明显升高,MDA含量明显减少,其差别均具有统计学意义(P<0.05)。病理学结果显示,缺血后处理组海马组织破坏和细胞损伤程度明显低于DHCA组,海马神经细胞的凋亡明显减轻。结论缺血后处理可以减轻炎症反应和改善氧自由基代谢,减少了脑组织细胞的凋亡和坏死,对DHCA大鼠具有显著的脑保护作用。
Objective Cerebral protection after cardiovascular surgery has become a focus of research in recent years.This study aimed to investigate the protective effect of ischemic postconditioning on the brain tissue of rats with deep hypothermic circulatory arrest（DHCA） and its possible mechanism.Methods Thirty-six clean adult male SD rats were randomly divided into a sham-operation,a DHCA and an ischemic postconditioning group.The DHCA model of global cerebral ischemia was established by the modified four-vessel method.The bilateral common carotid arteries in the sham-operation group were exposed without electric coagulation and clipping,those in the DHCA group blocked for 45 min and then opened up without any treatment,and those in the schemic postconditioning group subjected to three repeated cycles of ＂15 sec opened ＋ 15 sec blocked＂ and then fully opened up.Eight animals were killed in each group at 24 h after reperfusion to make brain tissue homogenate for the detection of TNF-α,IL-1β,IL-6,superoxide dismutase（SOD） activity and malondialdehyde（MDA） content.The other four rats in each group were subjected to pathological section of the brain tissue for observation of the ultrastructural changes in the brain tissue by electron microscopy and the apoptosis of hippocampal and cortical neurons by TUNEL.Results Compared with the sham-operation group,the DHCA and ischemic postconditioning groups showed a remarkable decrease in TNF-α,IL-1β,IL-6 and SOD activity,and a significant increase in MDA content（P0.05）.TNF-α,IL-1β,IL-6 and MDA content were evidently decreased,and SOD activity significantly increased in the ischemic postconditioning group as compared with the DHCA group（P0.05）.The brain tissue pathology revealed obviously less hippocampal histoclasia and cell injury in the ischemic postconditioning group than in the DHCA group.Conclusion Ischemic postconditioning can protect the brain of DHCA rats by reducing the inflammatory response,improving the metabolism of oxygen free radicals and decreasing the apoptosis and necrosis of brain cells.
出处
《医学研究生学报》
CAS
2010年第6期595-600,共6页
Journal of Medical Postgraduates
基金
南京军区医药卫生重点项目(08Z027)
关键词
深低温停循环
全脑缺血再灌注损伤
缺血后处理
脑保护
炎性因子
脑组织超微结构
凋亡
Deep hypothermic circulatory arrest
Global cerebral ischemia-reperfusion injury
Ischemic postconditioning
Cerebral protection
Inflammatory cytokines
Cerebral ultrastructure
Apoptosis
