上胸段硬膜外阻滞对脑血管痉挛兔脑组织GR表达及血清炎性细胞因子含量的影响

目的探讨上胸段硬膜外阻滞(HTEB)对蛛网膜下腔出血(SAH)后脑血管痉挛(CVS)兔的基底动脉周围脑组织糖皮质激素受体(GR)mRNA的表达及血清炎性细胞因子含量的影响。方法采用枕大池二次注血法制备兔SAH模型,将45只硬膜外阻滞成功的动物按随机数字表法随机分成3组(n=15):对照组、假手术组和HTEB组;然后各组再分为注血后l、7、14 d三个亚组(n=5)。用经颅多普勒超声检测注射前和注射后1、7、14 d动物基底动脉平均血流速度(Vm)。测量并比较各组基底动脉周围脑组织GR mRNA表达水平及血清炎性细胞因子肿瘤坏死因子-α(TNF-α)及白细胞介素(IL)-1、6]含量的差异。结果对照组基底动脉Vm、血清中TNF-α、IL-1和IL-6含量最高,HTEB组次之,假手术组最低,三组之间均差异显著(P<0.05)。脑组织中GR表达水平假手术组最高,HTEB组次之,对照组最低,三组之间差异显著(P<0.05)。结论HTEB可增加SAH后CVS的兔基底动脉周围脑组织GR的表达,并抑制TNF-α、IL-1、IL-6过度分泌,从而减轻CVS。

Effects of high thoracic epidural block on expressions of glucocorticoid receptor in the brain tissues surrounding the basal arteries and serum inflammatory cytokines content in rabbits with cerebral vasospasm fallowing subarachnoid hemorrhage

Objective To explore the effect of high thoracic epidural block(HTEB) on the expression of glucocorticoid receptor(GR) mRNA in the brain tissues surrounding the basal arteries and serum contents of inflammatory cytokines in rabbits with cerebral vasospasm(CVS) following subarachnoid hemorrhage(SAH).Methods HTEB was performed in 45 rabbits,who were randomly divided into 3 groups of 15 rabbits each,i.e.the sham-operation group,control group and HTEB treatment group.SAH was developed by two injection of autoblood into the cistern magna(0.5 ml/kg).The mean flow velocity(Vm) was determined by transcranial Doppler ultrasonography before SAH and 1,7 and 14 days after SAH.The expression of GR mRNA and the serum contents of inflammatory cytokines including tumor necrosis factor-α(TNF-α) and interleukin(IL)-1,6 were determined in all the groups.Results The Vm of the basilar arteries,and serum contents of TNF-α,IL-1 and IL-6 were significantly higher in the control group than those in HTEB treatment group(P<0.05),which were significantly higher than those in the sham-operation group(P<0.05).The level of GR mRNA expression in the brain tissues was signifcantly lower in the control group than that in HTEB group(P<0.05),which was significantly lower than that in the sham-operation group(P<0.05).ConclusionThe CVS following SAH may be relieved by the continuous HTEB in the rabbits.It is suggested that the HTEB-induced relief of CVS following SAH may be related to upregulation of GR expression in the brain tissues surrounding the cerebral vessels and inhibition of the inflammatory cytokine release produced by HTEB in the rabbits with SAH.