ABSTRACT
Objective:To investigate the effects of high thoracic epidural anesthesia (HTEA) on the cerebral blood flow (CBF) and hippocampal apoptosis-related proteins Bcl-2 and Bax during global cerebral ischemia and reperfusion (GCI) in rats.Methods:Fifteen-minute global ischemia was established by 4-vessel occlusion and epidural catheterization was performed through T4-5 intervertebral spaces in adult male Wistar rats.According to the different drugs infused into the epidural space,the rats were randomly divided into four groups:Sham group (0.9 ％ NaC1),Sham-HTEA group (0.25 ％ bupivacaine),GCI group (global cerebral ischemia,0.9 ％ NaC1) and HTEA group (global cerebral ischemia,0.25 ％ bupivacaine).And 0.25 ％bupivacaine or 0.9 ％ saline (20 μL·h-1) was infused continuously to the thoracic epidural space from 15 minutes before ischemia to 24 hours after reperfusion.Mean arterial pressure (MAP),heart rate (HR) and cerebral blood flow (CBF) were determined until 2 hours after reperfusion,and the hippocampal Bcl-2 and Bax proteins at 24 hours after reperfusion were examined by Western-blot.Results:Compared with the GCI group,HTEA group has no significant difference on MAP and HR during ischemia and 2 hours after reperfusion,andcompared with the Sham group,MAP in GCI group increased in ischemia 0 min and decreased in reperfusion 0 min.The CBF in HTEA group was significantly lower than that in GCI group (123.1％± 35.2％ vs 177.5％± 32.4％,P＜0.01) in reperfusion 10 min,and higher than that in GCI group during the hypoperfusion of 60 to 120 minutes after reperfusion (P＜0.05),and the ratio of Bax/Bcl-2 in hippocampus was significantly decreased in HTEA group 24 hours after reperfusion (P＜0.01).Conclusions:Continuous HTEA infusion of 0.25 ％ bupivacaine 20 μL ·h-1 could maintain the hemodynamic stability,and improve the CBF of hypoperfusion period in rats,as well as reduce the ratio of Bax/Bcl-2 at 24 hours after reperfusion.