SP600125抗大鼠脑缺血／再灌注中海马细胞凋亡的作用

Neuroprotective effect of SP600125, an inhibitor of JNK on brain ischemia/reperfusion in rats

目的探讨JNK特异性抑制剂-SP600125对大鼠脑缺血，再灌注（schemia／reperfusion，I／R）中海马细胞凋亡的作用。方法雄性SD大鼠54只，体重量230g-250g，采用双盲随机方法分成假手术组（SH组），I／R组，州K抑制剂SP600125组（SP组），每组根据再灌注时间分为30min、24h和72h 3个亚组，每亚组6只动物。采用4-VO法建立SD大鼠脑缺血模型，于缺血前30min侧脑室注射二甲基亚砜（dimethyl sulfoxide，DMSO），DMSO及JNK抑制剂SP600125（溶媒采用DMSO），容积均为10μl。脑I／R后24、72h测定其行为学改变，分别在30min、24h和72h等时间点，取脑组织，免疫组织化学方法测定海马CA1区Bcl-2和Bax蛋白表达阳性细胞数量和凋亡锥体细胞数量。结果全脑I／R使大鼠的垂直运动次数（4．8±2．0，9．1±3．4）和平衡木积分（2．3±1．2，3．5±0．9）显著减少（P〈0．05），I／R组的减少最为显著；脑I／R后海马CA1区凋亡神经元细胞数目（40．5±5．1）显著低于I／R组（P〈0．01）；全脑I／R 24h后，海马CA1区Bcl-2和Bax阳性锥体细胞数目（89．7±8．4，40．5±2．3）显著增加（P〈0．01），再灌注24h组增加最多；SP600125可以增加Bcl-2蛋白表达、减少Bax蛋白表达。结论SP600125对大鼠脑I／R中海马细胞的凋亡具有保护作用，此机制涉及抑制JNK信号转导通路。

Objective To investigate the effect of SP600125 on cell apoptosis in hippocampal CA1 after cerebral ischemia/ reperfusion （I/R） in rats and its possible mechanism. Methods 54 SD rats weighing 230 g-250 g were randomly divided into sham operation group （SH）, I/R group and JNK inhibitor SP600125 group （SP）. The rats received intracerebroventricularly DMSO（SH group）, DMSO（I/R group） and SP600125（ SP group, the use of DMSO solvent ） 30 min before isehemia. Each group was divided into 3 subgroups according to reperfusion time 30 rain, 24 h and 72 h （6 animals for each subgroup）. Global cerebral iscbemia was induced by four-vessel occlusion in rats. Behavioral test was performed at 24 h and 72 h after cerebral isehemia/reperfusion. Bax and Bcl-2 positive pyramidal cells as well as apoptotic positive pyramidal cells in the CA1 were quantified in immunohistochemieal stained or terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling（TUNEL） stained sections. Results Compared with SH group, cerebral I/R induced a decrease in standing times（4.8±2.0 vs 9.1±3.4, P〈0.05） and the beam-walking test scores（2.3±1.2 vs 3.5±0.9, P〈0.05）. Immunohistochemistry results showed that after ischemia/dreperfusion Hippocampal CA1 area Bcl-2 and Bax positive expression increased the number of pyramidal cells, 24 h of reperfusion the number of pyramidal cells shows that the expression of positive to the peak（40.5±5.1 ）（P〈0.01 ）, After I/R 24 h to 72 h, Positive expression to reduce the number of pyramidal cells （P〈0.05）, With the IR group, SP group Bcl-2-positive pyramidal cells increased the number of （89.7±8.4）（P〈0.05）, Bax- positive increase in the number of pyramidal cells less （40.5±2.3）（P〈0.05）. Conclusions SP600125 protects hippocampal CA1 neurons from death during global brain ischemia/reperfusion injury through inhibition of JNK signal transduction pathway.