地氟烷对全脑缺血再灌注损伤大鼠海马神经细胞超微结构及凋亡相关基因表达的影响

Effects of desflurane on the neuronal ultrastructure and expression of apoptosis-related genes in hippocampus of ischemia/reperfusion injury rats

目的探讨临床浓度地氟烷预处理对大鼠全脑缺血再灌注损伤后行为学、海马神经细胞超微结构及对凋亡相关基因bc l-2、bax表达的影响。方法72只W istar雄性大鼠随机分为3组(n=24),各组动物在不同时间点(再灌注后6 h、24 h和48 h)观察各项指标。对照组为假手术组;缺血组采用双侧颈总动脉夹闭+全身低血压法(MAP=40 mmHg±5 mmHg)制成脑缺血模型;地氟烷组在脑缺血前吸入1.0 MAC地氟烷1 h。实验过程中监测血压、心率、血气各项指标。各组动物手术后重置笼中自由饮食。分别在6 h、24 h和48 h进行动物行为学评分;之后10%多聚甲醛心脏灌洗,断头取脑,透射电镜观察海马区神经细胞超微结构的改变,免疫组织化学法观察凋亡相关基因bc l-2、bax在海马CA1区表达的动态变化。结果神经行为学评价显示,地氟烷组动物在缺血再灌注后各时间点的行为学表现优于缺血组(P<0.05);透射电镜结果显示地氟烷预处理可以改善神经细胞超微结构的改变;免疫组织化学结果显示,地氟烷组动物在各时间点促凋亡基因bax的表达低于缺血组(P<0.05);抗凋亡基因bc l-2的表达高于缺血组(P<0.05)。结论1.0 MAC地氟烷预处理对大鼠全脑缺血再灌注损伤有一定程度的保护作用,其机制与调控凋亡相关基因bc l-2、bax的表达有关。

Objective To investigate the effects of desflurane on the neuronal uhrastructure and expression of apoptosis-related genes bcl-2 and bax in ischemia/reperfusion rats. Methods Seventy-two Wistar rats were divided into 3 groups （n = 24 for each group）. The control group was sham operation group. The isehemia animal model was made by clamping bilateral common carotid arteries and hypotension （MAP =40 mmHg±5 mmHg）. The rats in the desflurane group underwent 1.0 MAC desflurane inhalation for 1 h before ischemia. The neurological behavioral assessments were evaluated by neurological tests. The changes of neuronal ultra structure were checked by transmission electromicroscope. The expression of apoptosis-related genes bel-2 and bax were examined by immunohistochemical method at 6,24,48 h after reperfusion. Results The neurological behavioral scores in the desflurane group were better than that in ischemia group at every time point （P〈0.05）. The CA1 pyramidal neuronal ultrastructures in desflurane group were improved compared with the ischemia group. The expression of bax gene in desflurane group was lower than that of ischemia group （P〈0.05） ; The expression of bcl-2 gene in desflurane group was higher than that of ischemia group（P〈0.05）. Conclusion 1.0 MAC of desflurane preconditioning has a brain protective effect on inschemia/reperfusion injury in rats. The mechanism of desflurane is related with the regulation of apoptosis-related genes bcl-2 and bax.