阿司匹林与尼莫地平合用对脑缺血再灌注损伤兔脑组织的保护

Combination of aspirin and nimodipine for protecting brain tissues of rabbits from cerebral ischemia reperfusion injury

目的:观察阿司匹林与尼莫地平合用对兔全脑缺血再灌注模型脑组织血栓烷A2、前列环素、前列腺素E2含量及对脑组织超微结构的影响,为临床两药合用提供理论依据。方法:实验于2004-10/12在潍坊医学院机能实验室完成。选用50只健康成年新西兰兔,随机分为5组,即假手术组、脑缺血再灌注模型组、阿司匹林组、尼莫地平组、阿司匹林+尼莫地平合用组,每组10只。除假手术组外,各组均按照Pulsinelli四动脉结扎法制作兔全脑缺血再灌注模型。各组家兔均于造模前4d开始灌胃给药,连续用药4d。假手术组和脑缺血再灌注模型组给予生理盐水3mL/kg;阿司匹林组给予阿司匹林2.35mg/(kg·d);尼莫地平组给予尼莫地平5.64mg/(kg·d);阿司匹林+尼莫地平合用组给予阿司匹林2.35mg/(kg·d)、尼莫地平2.82mg/(kg·d)。术后1h应用酶联免疫吸附竞争法测定脑组织中血栓烷A2、前列环素、前列腺素E2的含量;并应用透射电镜技术观察脑组织的超微结构改变。结果:50只家兔全部进入结果分析,无脱失。①缺血再灌注术后各组家兔脑组织中前列腺素E2、血栓烷A2、前列环素含量比较:与假手术组相比,脑缺血再灌注模型组脑组织中血栓素B2含量、血栓素B2/6-酮-前列腺素1α比值显著升高(P<0.05)。与模型组相比,阿司匹林组、尼莫地平组、阿司匹林+尼莫地平合用组脑组织中血栓素B2含量、血栓素B2/6-酮-前列腺素1α比值显著降低(P<0.05)。与阿司匹林组、尼莫地平组相比,阿司匹林+尼莫地平合用组脑组织中血栓素B2含量、血栓素B2/6-酮-前列腺素1α比值显著降低(P<0.05)。②缺血再灌注术后各组家兔脑组织的超微结构比较:假手术组神经元胞质内有大量线粒体,呈圆形或椭圆形;脑缺血再灌注模型组线粒体呈空泡样变;阿司匹林组和尼莫地平组少数线粒体内有小空泡;阿司匹林+尼莫地平合用组可见大量线粒体。结论:与阿司匹林、尼莫地平单独使用相比,两药合用具有更加显著的脑保护作用,可以明显改善脑组织的超微结构,其作用途径可能与两药从不同侧面降低脑组织中血栓素B2含量,维持血栓素B2/6-酮-前列腺素1α的平衡有关。

AIM： To investigate the effects of the combination of aspirin and nimodipine on the contents of thromboxane A2 （TXA2）, prostacyclin （PGI） and prostaglandin E2 （PGE2） as well as uhrastructure of brain tissue in rabbits with global cerebral ischemia/reperfusion, to provide the theoretical basis for clinical, usage of drugs. METHODS： The experiment was performed in the Function Laboratory of Weifang Medical College from October to December in 2004. Totally 50 New Zealand adult healthy rabbits were selected and divided randomly into five groups： sham operation group, ischemia/reperfusion model group, aspirin group, nimodipine group, aspirin ＋ nimodipine group with 10 ones in each group. Global cerebral ischemia/reperfusion models of rabbits were established with Pulsinelli 4-artery ligation, except the rabbits in the sham operation group. The rabbits in each group were treated drugs with gastric perfusion 4 days before establishing models for 4 days. The rabbits in the sham operation group and the ischemia/reperfusion model group were given 3 mL/kg saline. The rabbits in the aspirin group were given 2.35 mg/kg aspirin every day. The rabbits in the nimodipine group were treated with 5.64 mg/kg nimodipine every day. The rabbits in the aspirin ＋ nimodipine group were treated with 2.35 mg/kg aspirin and 2.82 mg/kg nimodipine every day. The contents of PXA2, PGI and PGE2 of brain tissue were determined with enzyme-linked immunosorbent assay （ELISA） 1 hour after operation. The change of uhrastructure in brain tissue was observed under transmission electron microscope. RESULTS： A total of 50 rabbits were involved in the final analysis, without drop out. ①Comparison of the contents of PGE2, PXA2 and PGI in brain tissue of rabbits after ischemia/reperfusion operation： Compared with the sham operation group, the content of TXB2 had increased and also the ratio of TXB2/6-keto-PGF1α （P 〈 0.05）. Compared with the model group, all the drug groups could significantly decrease TXB2 contents and TXB2/ 6-keto-PGF1α ratio in brain tissue （P 〈 0.05）. Compared with aspirin group and nimodipine group, the combination of aspirin and nimodipine had decreased obviously TXB2 content, TXB2/6-keto-PGF1αratio in brain tissue （P 〈 0.05）. ②Comparison of uhrastructure in brain tissue of rabbits of each group after ischemia/reperfusion operation： A mass of mitochondrium occurred in neuronal cytoplasm in the sham operation group, showed round or ellipse. The mitochondrium in the ischemia/reperfusion model group appeared vacuolar degeneration. Few mitochondrium in the aspirin group and the nimodipine group had small vacuoles. A large number of mitochondrium occurred in the aspirin ＋ nimodipine group. CONCLUSION： The combination of aspirin and nimodipine that has more obviously protective effects than application of aspirin or nimodipine alone can significantly improve the ultrastructure of brain tissue. Its role may be related with the decrease of TXB2 content in brain tissue and maintenance of TXB2/6-keto-PGF1αratio equilibrium affect by the two drugs in various ways.