热休克预处理对感染性脑水肿时神经细胞内钙的影响及机制探讨

The mechanism and effect of heat shock pretreatment on[Ca^(2+)]i of neurons in infectious brain edema

目的 探讨热休克预处理对感染性脑水肿时神经细胞内钙的影响及机制。方法 雄性 SD大鼠随机分为 (1)正常对照组 ;(2 )感染性脑水肿组 ;(3)生理盐水预处理组 ;(4 )热休克预处理组 ;(5 )内毒素预处理组。制备百日咳菌液脑水肿模型 ,Fura- 2 /AM荧光检测法测定突触体内游离钙浓度 ([Ca2 + ]i) ,同时测定脑含水量、伊文思蓝和 Na+含量 ;原位杂交和 Western印迹分析检测 HSP70的表达。结果 热休克预处理组和内毒素预处理组[Ca2 + ]i含量较感染性脑水肿组明显降低 (P<0 .0 1) ;[Ca2 + ]i含量的变化与脑含水量、伊文思蓝含量、Na+含量的改变呈直线正相关。热休克和内毒素预处理后 HSP70 m RNA和 HSP70明显增加。结论 热休克和内毒素预处理均可减少感染性脑水肿时 Ca2 +细胞内流 ,这种作用与其诱导 HSP70的基因表达增加有关。

Objective To study the mechanism and effect of heat shock pretreatment on the intracellular calcium of neurons in infectious brain edema. Methods Male Sprague Dawley (SD) rats were randomly divided into five groups:(1)Normal control group ;(2)Infectious brain edema group;(3)Normal saline control group;(4)Heat shock pretreatment group;(5)Lipopolysaccharide(LPS) pretreatment group. An animal model of infectious brain edema by pertussis bacilli (PB) was used. The free intracellular calcium concentration ([Ca 2+ i]) was measured by Fura 2/AM in synaptosomes of cerebral cortex. Water content, Evans blue content, Na + content in brain tissues were measured. Heat shock protein (HSP) 70 mRNA and HSP70 of brain tissues were detected by In situ hybridization and Western blot analysis. Results The [Ca 2+ ]i concentration of synaptosomes were significantly decreased in heat shock pretreatment group and LPS pretreatment group than in Infectious brain edema group (P< 0.01 ). There was a positive linear relationship between [Ca 2+ ]i concentration and water content, Evans blue and Na + content . HSP70 mRNA and HSP70 of brain tissue was increased after heat shock and LPS pretreatment. Conclusions The Ca 2+ influx were inhibited by heat shock and LPS pretreatment, which may be relational with the HSP70 gene expression increased.