心肺复苏后吸入七氟醚通过调控Bcl—2／Bax减少神经元凋亡

Sevoflurane inhalation attenuates the neuron apoptosis by modulation of Bcl -2/Bax expression after cardiac arrest in rats

目的 观察大鼠心肺复苏（CPR）自主循环恢复（ROSC）后吸入七氟醚对大脑皮层神经细胞凋亡的影响。方法 建立大鼠室颤后CPR模型（VF/CPR）。30只Wistar大鼠随机分为假手术组（Sham group）6只，七氟醚组（Sevo group）12只，对照组（Control group）12只。Sham组仅麻醉及气管插管，Sevo组在ROSC后立即吸入2.4%七氟醚10 min，Control组常规心肺复苏。ROSC 24 h后采用神经缺损评分（Neuro-Deficit Scoring, NDS）量表对大鼠神经功能进行评分；电镜观察线粒体损伤程度和TUNEL法对大脑皮层神经元细胞凋亡进行检测； Western blot检测Bcl-2、Bax和细胞色素C的蛋白表达水平，免疫组化检测活化的半胱氨酸蛋白酶（Cleaved-Caspase 3）的蛋白表达水平。结果 实验前三组动物体质量、心率、平均动脉压差异无统计学意义，复苏中的CPR时间、除颤次数、肾上腺素使用剂量差异无统计学意义。ROSC 24 h后，Sevo组的NDS评分明显高于Control组。电镜下，Sevo组线粒体结构损害程度较轻；TUNEL法显示，凋亡细胞比例明显低于Control组［（12±6）% vs.（22±8）%，P＜0.01］。其次，Sevo组Bcl-2/Bax蛋白比值明显高于Control组［（54±11）% vs.（28±9）%，P＜0.01］，并可抑制细胞色素C的释放，减少Cleaved-Caspase 3的激活。结论 ROSC后吸入七氟醚，可减轻大脑皮层神经元凋亡，改善复苏后脑功能，其机制可能与调节Bcl-2/Bax表达有关。

Objective To investigate the effect of sevoflurane on neuron apoptosis administered after reaching restoration of spontaneous circulation （ROSC） during cardiopulmonary resuscitation （CPR） in rats. Methods The cardiac arrest model was established by ventricular fibrillation. Thirty male Wistar rats were assigned randomly into three groups. Six rats in the sham group were anesthetized and intubated without induction of cardiac arrest. 12 rats in the Sevo group were exposed to 2.4% minimal alveolar concentration（1MAC） of sevoflurane after reaching ROSC for 10 mins. 12 rats in the control group received the standard CPR only. 24 hours after ROSC, neuro- deficit scoring （NDS） was used to assess the neurological outcome. Then, all the rats were sacrificed with deep anesthesia, mitochondrial injury was observed by electron microscopy. TUNEL assay was used to count the apoptosis neurons ratio. Additionally, the level of Bcl -2, Bax, cytochrome C proteins expression were detected by Western blot. Cleaved caspase - 3 expression was evaluated by immunohistochemical staining. Results There were no statistical difference in weight, heart beat, mean arterial pressure （MAP） among the three groups at the beginning of the experiment, and the CPR duration, defibrillation times, epinephrine dosage were not statistically significant between Sevo group and control group. NDS was higher in Sevo group than control group. Less alternation of the mitochondrial ultra - structure under sevoflurane treatment was revealed. The apoptosis neurons ration in Sevo group was markedly reduced [ （ 12 ±6）% vs. （22 ±8）%, P〈0.01]. Furthermore, compared to control group, the ratio of Bcl-2/ Bax was higher in sevo group[ （54 ± 11）% vs. （28 ±9）%, P 〈0.01], while the expression of cytochrome C, active Cleaved Caspase -3 were lower. Conclusion The administration of sevoflurane after ROSC can inhibit neuronal apoptosis, mitigate neurological function injury partly attributed to the modulation of Bcl -2/Bax expression.