Lactuside B增加大鼠脑缺血后海马和纹状体GRP78 mRNA的表达

Lactuside B increased GRP78 mRNA expression of hippocampus and striatum after cerebral ischemic injury in rats

目的:探讨高翅果菊提取物Lactuside B对大鼠脑缺血后海马和纹状体GRP78mRNA表达的影响。方法:清洁Ⅱ级SD雄性大鼠,体质量280～320g,随机分为6组,即:模型组、假手术组、阳性药物对照组(尼莫地平1mg·kg-1)、Lactuside B12.5、25和50mg·kg-1组,每组8只。采用大鼠大脑中动脉阻塞法复制脑缺血再灌注损伤模型,所有大鼠均阻塞2h再灌注。各组动物于再灌注后给予腹腔注射相应的实验药物(模型组、假手术组动物给予等体积的纯化水),bid,给药1d和3d后分别处死各组的4只动物取脑备用。神经缺失症状评分法进行神经功能测定;RT-PCR技术分别检测大鼠海马和纹状体不同时间段GRP78mRNA的表达。结果:给药1d和3d后,Lactuside B各剂量组动物的神经行为学评分均降低,与模型组比较均有显著性差异(P<0.05或P<0.01);Lactuside B各剂量组动物海马和纹状体的GRP78mRNA表达均明显增多,与模型组比较差异有显著性(P<0.05或P<0.01);除用药1d时纹状体GRP78mRNA的表达在各组间有量效关系外,其余各组的高剂量组作用较差;海马的Lactuside B各剂量组GRP78mRNA的表达优于阳性对照组(P<0.05或P<0.01),而纹状体只有用药3d时此种作用才明显。结论:Lactuside B的抗脑缺血作用与其持续上调海马和纹状体的GRP78mRNA表达有关。

OBJECTIVE To explore the effects of GRP78 mRNA expression in rat＇s hippocampus and striatum after cerebral isehemic injury. METItODS Grade 1I clean male SD rats, weighing 280-32k g, were randomly divided into 6 groups： mode[ group, sham-operated group, positive control group （nimodipine 1mg kg- 1 ）, lactuside B 12. 5,25 and 50 mg. kg- 1 groups, 8 rats in each group. The models of cerebral ischemia- reperfusion injury were replicated by the occlusion of middle cerebral ar tery in rats,which were reperfused 2 h after operation. All the animals were injected corresponding experimental drugs by i. p. at different times （the animals of sham-operated group and model group were injected with distilled water）, 4 animals were sac- rificed and rats brains were taken for reserve after reperfusion 24 h and 72 h. The neurological deficits scores were used for jud ging neurological functions, RT-PCR was used to detect expression of GRP78 mRNA in the hippocampus and striatum at differ ent times. RESULTS The neurological behavior scores were lowered in all animals of lactuside B group 1 d and 3 d after admin istration, and there were significant differences as compared with the model group （P^0. 05 or P〈0. 01）. GRP78 rnRNA were significantly increased in all lactuside B group , compared With the model group （P〈0. （15 or P〈0. 0l）. Apart from the striatum in rats administrated for I d, there was no apparent close-effect relationship existing in the expression of GRP78 mR NA of the most LH group. All the lactuside B group when compared with the positive control group showed significant differ- ences in the expression of GRP78 mRNA of the hippocampus （P〈0. 05 or P〈0. 01 ）, but the action on striatum was obvious when the rats administrated for 3 d. CONCLUSION Increasing GRP78 mRNA expression of hippocampus and striatum con- cerned with the anti- ischemic actions of lactuside B.