经颈动脉直接注入外源性降钙素基因相关肽对局灶性脑缺血再灌注大鼠海马区Fas蛋白表达的影响

Effects of the injection of exogenous calcitonin gene related peptide directly through carotid artery on the expression of Fas protein in hippocampus of rats with focal cerebral ischemia/reperfusion

目的:探讨经颈动脉直接注入外源性降钙素基因相关肽对局灶性脑缺血再灌注大鼠海马细胞表面死亡受体Fas蛋白表达的影响。方法:实验于2004-01/12在中国医科大学基础医学院神经生物实验室进行,取雄性SD大鼠90只,随机分为3组,每组30只:①假手术组:分离血管,不插线栓。②缺血再灌注组:用线栓法制备大鼠大脑中动脉阻塞模型,在脑缺血2h后拔出栓线再灌注,再灌注即刻经颈动脉注入生理盐水1mL。③降钙素基因相关肽组:同前造模,再灌注即刻经颈动脉注入降钙素基因相关肽0.5mL。后两组动物再灌注后6,12,24,48,72h麻醉后断头处死,假手术组同时处死,每个时间点各6只。应用免疫组化和显微图像分析方法检测局灶性脑缺血再灌注大鼠海马Fas蛋白的表达。结果:经补充后90只动物进入结果分析。假手术组大鼠海马未见Fas阳性细胞表达,24h平均吸光度值为0.1910±0.0142;缺血再灌注组于再灌注6h后在海马区可见Fas阳性细胞,随着再灌注时间的延长,大鼠脑皮质及海马Fas表达进一步增加,于再灌注24h时达高峰,平均吸光度值为0.3607±0.0388,以后开始逐渐下降;降钙素基因相关肽组:各相应时间点大鼠脑皮质及海马区Fas阳性细胞平均吸光度值明显低于缺血再灌注组,其再灌注24h平均吸光度值为0.3030±0.0011。结论:经颈动脉直接注入外源性降钙素基因相关肽可下调缺血神经元Fas蛋白的表达,对缺血神经元有保护作用。经颈动脉直接注药,保持了脑组织较高的药物浓度,且减少了药物通过静脉、腹腔内给药经体循环而造成的损失。

AIM： To study the effects of ectogenesis calcitonin gene related peptide （CGRP） injected directly through carotid artery on the expression of hippocampus cell surface receptor Fas protein in rat with focal cerebral is-chemia/reperfusion （ I/R ）. METHODS： The experiment was performed in the Laboratory of Neurobiology of Basic Medical College of China Medical University from January to December 2004. Totally 90 SD rats were randomly divided into three groups with 30 in each group： ① Sham operation group： dissociation blood vessel, without insert line; ② I/R group： using line-lock method to make rat middle cerebral artery occlusion （MCAO） focal cerebral ischemia model, after 2 hours cerebral ischemia,the line was extracted with carotid artery to enter saline 1 mL as reperfusion. ③ CGRP group： same the I/R group, after 2 hours cerebral ischemia,with carotid artery to enter CGRP 0.5 mL as reperfusion. The rats in the later two groups with various time points after anesthesia at 6 hours, 12 hours, 24 hours, 48 hours and 72 hours with 6 rats in every time point were sentenced to death, meanwhile, the rats in sham operation group were sentenced to death. The expression of Fas protein in hippocampus was detected with immunohistochemical methods and analyzed by micreimage analysis system. RESULTS： Ninety rats were involved in the result analysis after compensation. Fas protein positive cells were not find in sham group, and the average absorbance （A） values was 0.1910±0.0142; but were find in focal cerebral I/R group after reperfusion 6 hours, with reperfusion time elongation, expression of fas protein increase .At 24 hours expressed the peak, average A value was 0.3607±0.0388, and then began to decrease gradually; The CGRP group： The average Avalues of Fas protein positive cell in brain cortex and hippocampus area were significantly lower than that in I/R group, at reperfasion 24 hours averageA values was 0.3030±0.0011 （P〈 0.01 ）. CONCLUSION： The ectogenesis CGRP injected directly through carotid artery can decrease the expression of Fas protein in ischemic neurons, has protective effect on ischemic neurons, The drug injection through carotid artery directly maintain the higher drug concentration in brain tissue, and decrease the loss due to the administration through systemic circulation by vein and abdominal cavity.