The Effect And Mechanism Of Stellate Ganglion Block On Cardiopulmonary Bypass-Induced Cerebral Injury In Rats

Objective:To investigate effects of stellate ganglion block(SGB) on cerebral injury in rats underwent cardiopulmonary bypass (CPB) and explore the potential molecular mechanisms.Methods:Sixty-four male Sprague-Dawley rats, weighting 300-350g,were randomly divided into four groups(n=16 per group):sham operation group (S), SGB group (R), CPB group (C), SGB and CPB group (RC). After anesthesia,0.25 percent bupivacaine 0.2ml was injected to established SGB model in group R and RC.Then intravenous catheters were placed into bilateral femoral artery and the right jugular vein in each group,and deal with the following processing:The rats of group S and group R were monitored for two hours, the rats of group C and group RC underwent CPB for two hours.The vital signs were monitored during experimental process in each group. Venous blood samples were taken at Oh (TO), 1h(T1),2h(T2) after CPB for determining the serum concentration of endothelin-1(ET-1)and calcitonin gene-related peptide(CGRP) by ELISA. The hippocampus pathological change was observed through HE staining. The number of apoptotic hippocampus cells and the expression of GSK-3β, β-catenin, Cytc, Survivin were also measured.Results:The SGB and CPB model of rats were successfully established. Hippocampal cells of group S and R arranged in neat rows, and the cell structure was complete.However,hippocampal cells arranged in a mess and showed swelling, and the boundary of nucleas and membrane was unclear in group C and RC.The injuries of hippocampus lightened significantly in group RC than that in group C. The indicators of Group S and R showed no significant difference (P> 0.05).Compared with group S,the serum concentration of ET-1 at T1 and T2 in group C and RC were increased (P<0.05), instead, the serum concentration of CGRP were decreased. Compared with group C, the serum concentration of ET-1 in group RC was lower at T1 and T2 (P<0.05), while the serum concentration of CGRP was higher (P<0.05). Compared with group S,the apoptosia index (AI), the mRNA and protein levels of GSK-3β and Cytc in group C and RC were increased (P<0.05), instead, the mRNA and protein levels of Survivin were decreased. Compared with group C, the AI,the mRNA and protein levels of GSK-3β and Cytc were lower in group RC (P<0.05), while the mRNA and protein levels of Survivin were higher (P<0.05). There was no significant difference of the mRNA and protein levels of β-catenin among groups.Conclusion:The cerebral injury of rats had been caused by CPB, SGB could decrease the surm concentration of ET-1, increase the surm concentration of CGRP, down-regulate Cytc and GSK-3β levels, and up-regulate Survivin levels, thus to regulate the contraction and relaxation of cerebral vascular and reduce myocardial apoptosis, which may finally help to protect brain of rats underwent CPB from injuries.