大鼠脑线粒体和突触体外周型苯二氮受体的增龄变化

Age-related changes of peripheral-type benzodiazepine receptors in mitochondria and synaptosome in the brain in rats

目的探讨衰老过程大鼠脑组织线粒体和突触体外周型苯二氮受体(PBRs)的动态变化。方法雌性SD大鼠分为乳鼠组、3、12、15、18、24和30月龄组。动物断头后迅速取脑,采用梯度离心法提取大脑皮质线粒体和海马突触体,应用放射配基结合实验测定PBRs结合活力。结果7组比较,皮质线粒体和海马突触体PBRs结合活性差异显著(均P<0.05～0.001)。15月龄以前皮质线粒体和海马突触体PBRs结合活性逐渐下降(P<0.01),15～24月龄PBRs结合活性有下降趋势,但变化不显著(P>0.05)。30月龄组皮质线粒体和海马突触体PBRs结合活性显著高于3月龄组(P<0.01),低于乳鼠组(P<0.05)。结论大脑皮质线粒体、海马突触体PBRs结合活性呈明显增龄性改变,PBRs参与了脑老化过程。

Objective To evaluate the dynamic changes of peripheral-type benzodiazepine receptors （PBRs）in mitochondria and synaptosomes in the brain in rats during aging. Methods Sprague-Dawley female rats were divided into seven groups,including neonate rats and aged rats of 3,12,15,18,24 and 30 months. All rats were sacrificed by decapitation to remove immediately brains. Mitochondrial fractions from cerebral cortex and synaptosomal fractions from hippocampus were prepared by gradient centrifugation. The,specific binding assay of radioactive PBRs antagonist [^ 3H ] PK11195 to membrane was performed. Results The mitochondrial and synaptosomal PBRs binding activity （ both P 〈 0. 05 -0. 001 ）had significant difference among seven groups, those before 15 months group gradually decreased （P 〈 0. 01 ）, those in 15 -24 months goups had decline trend but no significance （P 〉0. 05） ,and those in 30 months group were higher than those in 3 months group （P 〈 0.01 ） ,lower than those in neonate mice group （ P 〈 0. 05 ）. Conclusions PBRs binding activity in cortex mitochondria and hippocampus synaptosomes could change with aging. PBRs might be involved in the pathogenesis of aging in the rat＇s brain.