姜黄素对全脑缺血再灌注大鼠海马高迁移率族蛋白1表达及凋亡的影响

Effect of curcumin on the expression of high mobility group box 1 and apoptotic neurons in hippocampus after global cerebral ischemia reperfusion in rats

目的 观察姜黄素对全脑缺血再灌注后大鼠海马高迁移率族蛋白1（HMGBl）表达及神经元凋亡的影响.方法 雄性SD大鼠192只,随机分成假手术组（SH组）、缺血再灌注组（IR组）、姜黄素组（Cur组,200 mg/kg缺血前1 h腹腔注射）及溶剂对照组（SC组）.建立四动脉阻塞全脑缺血冉灌注模型,在再灌注后1、3、5、7 d处死大鼠;HE染色观察海马神经细胞形态,TUNEL法检测海马CA1区神经元凋亡,免疫蛋白印迹法对海马HMGBI表达行半定量分析.结果 IR组及SC组海马CA1区各点凋亡细胞数明显多于sH组,Cur组再灌注1、3、5、7 d凋亡细胞数分别为IR组的41%、57%、65%、70%（P＜0.05）.IR组（0.685±0.050）及Sc组（0.695±0.053）再灌注1 d HMGB1表达水平明显低于SH组（0.977±0.063,P＜0.05）,再灌注3 d（1.360±0.045,1.353±0.045）、5 d（1.342±0.046,1.338±0.047）、7 d（1.319±0.052,1.322±0.035）表达水平明显高于SH组（0.992±0.031,0.978±0.090,0.992±0.075,P＜0.05）.Cur组再灌注1 d HMGB1表达水平（0.842±0.063）明显高于IR组、SC组但低于SH组（P＜0.05）,再灌注3 d（1.125±0.023）、5 d（1.098±0.073）、7 d（1.087±0.089）表达水平明显低于IR组及sC组（P＜0.05）.SC组与IR组相比差异无统计学意义.结论 SD大鼠全脑IR后1 d海马HMGB1表达明显减少,后升高并持续高表达至再灌注7 d.姜黄素减轻海马神经元凋亡及损伤的机制可能与抑制HMGB1的合成与释放有关.

Objective To explore the effects of curcumin on the expression of high mobility group box 1（HMGB1）and apoptotic neurons in hippocampus after global cerebral ischemia/reperfu8ion in SD rats.Methods A total of 192 male SD rats were randomly divided into 4 groups：sham group（SH）,ischemia-reperfusion group（IR）,cureumin group（Cur）and solvent control group（SC）.Bilateral vertebrate arteries were electroeauterized and bilateral comlnon carotid arteries libemted in 3 ischemic groups.Isasteric curcumin solutions（200 mg=/kg）or menstruum were injected intraperitoneally at 1 hour preischemia in Cur and SC groups.The rats in each group were ligated for 15 minutes and then decapitated at slides.Apoptotic neurons were detected in CA1 region by TUNEL（terminal deoxynueleotidyl transferasemediated dUTP-biotin nick end labeling）.Western blot was used to make a semi-deternination of HMGB1 expression.Results At each time point,tlle number of apoptotic neurons was much more in IR and SC groups than that in SH group（P＜0.05）.And the number of apoptotie neurons at 1,3,5,7 d postreperfusion was only 41%,57%,65%and 70%in Cur group respectively（P＜0.05）.The exPressional level of HMGB1 in IR and SC groups was significantly lower at 1d post-reperfusion（0.685±0.050：0.695±0.053 vs 0.977±0.063,P＜0.05）.And it was significantly higher at 3,5,7 d post-reperfusion in IR and SC groups than that in SH groups（1.360±0.045/1.353±0.045;1.342±0.046/1.338±0.047;1.319±0.052/1.322 ±0.035 vs 0.992±0.031;0.978±0.090;0.992±0.075,P〈0.05）.The level at 1 d post-reperfusion（0. 842±0. 063）in Cur group was significantly higher than that in IR and SC groups but lower than that in SH group. And it was lower at 3, 5, 7 d post-reperfusion （1. 125 ± 0. 023, 1. 098 ±0. 073, 1. 087 ± 0. 089） than those in IR and SC groups （P＜0. 05）. There was no significant difference of HMGB1 expression level between IR and SC groups. Conclusion The expression level of HMGB1 in hippocampus is significantly reduced at 1 d post-reperfusion. Then it significantly increases and a high level is maintained until 7 d after global cerebral ischemia/reperfusion. Cureumin can reduce hippocampal neuronal apoptosis and injury. Such an effect may be due to an inhibition of the synthesis and release of HMGB1.