Effects Of High Thoracic Epidural Block On Expressions Of Glucocorticoid Receptor And Cytokine Release Changes In Cerebral Vasospasm In Rabbits

Objectives: To approach the effects of high thoracic epidural block(HTEB)on expressions of glucocorticoid receptor and cytokine release changesin cerebral vasospasm following subarachnoid hemorrhage (SAH) in rabbits.Methods: The HTEA model at T6～7epidural space was established in45rabbits, who were randomly assigned to3groups of15rabbits each, i.e. the sham-operated group(N), Control group (S), HTEB treatment group(HS). SAH was developed by two injection of autoblood into the cisternmagna (0.5ml/kg), Transcranial Doppler ultrasonography was used todetect the basilar artery mean flow velocity (Vm)1,7and14days afterSAH.Tumor necrosis factor-(TNF-)，interleukin-1(IL-1) and interleu-kin-6(IL-6) concentration is determined by ELISA in1,7and14days afterSAH. The changes in histological morphology of the basilar artery wereobserved under a light Microscope. Glucocorticoid receptor (GR)m RNA weremeasured in the cells nearby basillary artery by reverse trans-cription PCR(RT-PCR).Results: Compared to N group, The Vm and Vp of the basilar artery werefound to be elevated, the lumina of the basilar arteries became narrowand the walls of the basilar artery were thicker; The Vm and Vp of thebasilar artery in the S group was significantly faster than that in theHS group (P<0.05).Pathological observations showed that in the S groupthe lumina of the basilar arteries was narrower and the basilar arterywalls were thicker than the HS group. Compared with N group，GR mRNA levels in S group and HS group decreased significantly(P<0.01); Proinflamma-tory cytokine (TNF-、IL-1、IL-6)release in S group and HS group was higherthan that in N group(P<0.01). GR mRNA levels in HS group was higher thanthat in S group(P<0.05)；Vm of the basilar artery and Proinflammatorycytokine (TNF-、IL-1、IL-6)release in HS group was lower than that inS group(P<0.05).Conclusion: This study demonstrates that prophylactic continuous HTEBprevents SAH-associated CVS in an animal model. It possibly throughameliorating GR function and controlling inflammatory response topreventive effect on SAH-associated CVS in rabbits．...