胰岛素对心肺复苏大鼠神经元凋亡及Bcl-2,Bax mRNA表达的影响

目的 探讨脑室内注射胰岛素对心肺复苏(cardiopulmonary resuscitation,CPR)后大鼠海马CA1区神经元凋亡和对抑凋亡因子Bcl-2,促凋亡因子Bax mRNA表达的影响.方法 实验地点在首都医科大学宣武医院试验动物中心.30只雄性SD大鼠随机(随机数字法)分为假手术组(对照组,n=6)、心肺复苏组(复苏组,n=12)及CPR后胰岛素干预组(胰岛素组,n=12).经食道超速起搏诱发6min室颤制备大鼠CPR模型；以CPR后大鼠恢复室上性心率、收缩压超过60 mmHg(1 mmHg=0.133 kPa)并持续10 min以上,作为自主循环恢复(ROCS)标准；ROCS 10 min后,胰岛素组大鼠经立体定位仪定位,脑室内注射12.5 μL(1 U)胰岛素,其余2组大鼠注射等量生理盐水.维持生命体征,CPR后24,72 h,应用实时荧光PCR (Realtime-PCR)测定海马CA1区神经元Bcl-2,Bax mRNA的表达量；CPR后7d,应用TUNEL染色检测海马CA1区神经元凋亡；CPR前后监测大鼠静脉血糖变化.计量资料采用均数±标准差(-x±s),组间比较采用单因素方差分析(ANOVA)；相关性统计应用Pearson相关分析,以P＜0.05为差异具有统计学意义.结果 ①CPR后24,72 h,胰岛素组大鼠Bcl-2 mRNA表达量均高于复苏组(1.45±0.05) vs.(0.79±0.01)；(0.95±0.06) vs.(0.35±0.03),差异具有统计学意义(P＜0.01).组内比较发现,胰岛素组、复苏组72 h表达均低于24 h(P＜0.01).而胰岛素组与复苏组Bax mRNA表达差异无统计学意义(P＞0.05),胰岛素组、复苏组72 h与24h比较差异无统计学意义(P＞0.05).②CPR后7d,胰岛素组大鼠海马CA1区神经元凋亡计数,复苏组(124.75±17.35)个/mm2明显高于对照组(5.12±3.26)个/mm2和胰岛素组(92.79±7.49)个/mm2,差异具有统计学意义(P＜0.01).③各组大鼠各时间点外周静脉血糖比较无统计学意义(P＞0.05).结论 脑室内注射1U胰岛素,能够促进CPR后大鼠神经元促凋亡因子Bcl-2 mRNA的表达,抑制神经元凋亡,具有神经保护作用.脑室注射1U胰岛素不降低外周血糖.

The effect of insulin on the expressions of Bcl-2, Bax mRNA and hippocampus neuronal apoptosis in rats after cardiopulmonary resuscitation

Objective To explore the effects of intraventricular administration of insulin on the expressions of Bcl-2,Bax mRNA and neuronal hippocampus apoptosis in rats after cardiopulmonary resuscitation (CPR).Methods This experiment was implemented in the animal Laboratory center of Xuanwu Hospital of Capital Medical University.Thirty male SD rats were randomly (random number)divided into three groups:control group (n=6),CPR group (n=12),insulin treated group ( n =12).CPR was performed at 6 minutes after ventricular fibrillation induced by transesophageal overdrive pacing.Resuscitation procedures lasted until restoration of spontaneous circulation (ROSC).ROSC was defined as the recovery of the supraventricular heart rates and the increase of mean arterial pressure (MAP) ＞ 60mmHg for more than 10 minutes.Ten minutes after ROSC in rats,12.5 μL ( 1 U) regular insulin was injected into the left ventricle in the insulin group,and 12.5 μL isotonic saline was injected the control and CPR groups at least 10 minutes.Real-time PCR was used to observe the expressions of Bcl-2,Bax mRNA in hippocampus CAI after reperfusion 24 h and 72 h.TUNEL staining was used to observe the neuronal apoptosis in all groups after reperfusion 7 days.Blood glucose was monitored in rats before and after CPR.Results ① The Bcl-2mRNA in insulin groups were significantly higher than those in the CPR group after 24 h and 72 h (P ＜0.01 ).The expression of Bcl-2 mRNA in 24 h insulin group were significantly higher than those in 72 h insulin group ( P ＜ 0.01 ) ; There were no significantly different in the Bax mRNA between insulin groups and the CPR and the control group after 24 h and 72 h ( P ＞ 0.05 ) ; ②After CPR 7 d,the apoptotic neurons of hippocampal CA1 area in the CPR group ( 124.75 ± 17.35 ) were significantly higher than those in the control group (5.12 ± 3.26) ( P ＜ 0.01 ) and the insulin group (92.79 ± 7.35 )(P ＜0.01 ); the apoptotic neurons in the insulin group were higher than those in the control group (P ＜0.0l ),and the differences were statistically significant.③There were no significant difference in venous blood glucose in the CPR and insulin groups (P ＞ 0.05).Conclusions Insulin may regulate Bcl-2mRNA expression in hippocampus,inhibit neuronal apoptosis and protect neurons after CPR in rats.