西洛他唑对全脑缺血大鼠学习记忆功能及半胱氨酸天冬酶-3表达的影响

Effects of Cilostazol on learning and recalling abilities and caspase-3 expression after global cerebral ischemia-reperfusion in rats

目的研究西洛他唑对全脑缺血大鼠学习记忆功能及半胱氨酸天冬酶-3(caspase-3)表达的影响。方法采用四血管阻断法制作大鼠全脑缺血再灌注模型。将SD大鼠随机分为假手术组(n=8×1)、缺血模型组(n=8×7)和治疗组(n=8×7)。治疗组于缺血前6 h和2 h各灌胃给予西洛他唑(30 mg/kg),以后每隔24 h重复给药,其他各组灌胃给予30%二甲基亚砜(30 mg/kg)。缺血模型组和治疗组于缺血10 min再灌注,6、12、24、48、72 h、5 d和7 d 7个亚组灌注后断头取脑,采用免疫组织化学方法分析再灌注后不同时间点海马CA1区caspase-3表达水平的变化。另取24只大鼠随机分为假手术组、缺血模型组及治疗组,每个亚组8只。应用Morris水迷宫对全脑缺血再灌注7 d的大鼠进行缺血后学习记忆功能的测定。结果caspase-3在假手术组极少见阳性表达;缺血模型组caspase-3的表达于再灌注6 h增加,72 h达高峰,7 d接近正常;治疗组48 h7、2 h5、d和7 d亚组caspase-3平均阳性细胞数明显低于缺血模型组(P<0.05);与假手术组比较,5 d之中缺血模型组和治疗组平均逃避潜伏期明显延长(P<0.01);与缺血模型组比较,前4 d治疗组平均逃避潜伏期明显缩短(P<0.01),第5天两组大鼠的平均逃避潜伏期差异无统计学意义(P>0.05)。结论西洛他唑可以有效地抑制caspase-3升高,这可能是西洛他唑改善缺血大鼠学习记忆功能的机制之一。

Objective To explore the effects of Cilostazol on learning and recalling abilities and caspase-3 expression after global cerebral ischemia-reperfusion in rats. Methods Transient global cerebral ischemia was induced by four-vessel occlusion in Sprague-Dawley（ SD ） rats, which were randomly divided into the sham-operation group（ n = 8 × 1 ）, the model group（ n = 8 × 7） and the Cilostazol-reatment group（ n = 8 × 7）. Rats in the treatment group received two oral administrations of cilostazol at 6 h and 2 h before global cerebral ischemia, then they were given cilostazol every 24 h. Rats in other groups were given the same volume of 30% dimethyl sulfoxide. Rats in the model group and the treatment group were decapitated at 6, 12, 24, 48, 72 h, 5 d and 7 d after 10 min cerebral ischemia. Then the expression of caspase-3 in the CA1 region of the hippoeampus was determined by immunohistochemistry. The other 24 rots were randomly divided into 3 groups： the sham-operation group（ n = 8）, the isehemiarepefusion group（ n = 8） and the treatment group（ n = 8）. Leaming and recalling abilities of rats at 7 d after global iachemiarepefusion were determined by the Morris water maze. Results Caspase-3 was scaxely expressed in the sham-operation group, while it increased at 6 hours, peaked at 72 hours, and deceased nearly to the normal level at day 7 in the model group; mean positive caspase-3 cells in the CA1 region were obviously lower in 48, 72 h, 5 d and 7 d subgroups of the treatment group than those in the model group（P〈 0.05）. Within 5 days, Escape Latency（EL） was significantly longer in the ischemia-reperfusion group and the treatment group than in the sh_am-operation group（ P 〈0.01, P 〈0.05 respectively）; within 4 days, Escape Latency（EL） was significantly shorter in the treatment group than that in the isehemia reperfusion group（ P 〈 0. 01 ） ; whereas on day 5, no significant differences were found in the two groups. Conclusions Cilostazol can effectively inhibit the increase of caspase-3 levels, which may be one mechanism of its increasing learning and recalling abilities of rats.