Hu B R, Liu C L, Ouyang Y, Blomgren K, Siesjö B K
Laboratory of Neurochemistry, Queen's Medical Center, Honolulu, Hawaii 96813, USA.
J Cereb Blood Flow Metab. 2000 Sep;20(9):1294-300. doi: 10.1097/00004647-200009000-00003.
The involvement of caspase-3 in cell death after hypoxia-ischemia (HI) was studied during brain maturation. Unilateral HI was produced in rats at postnatal day 7 (P7), 15 (P15), 26 (P26), and 60 (P60) by a combination of left carotid artery ligation and systemic hypoxia (8% O2). Activation of caspase-3 and cell death was examined in situ by high-resolution confocal microscopy with anti-active caspase-3 antibody and propidium iodide and by biochemical analysis. The active caspase-3 positive neurons were composed of more than 90% HI damaged striatal and neocortical neurons in P7 pups, but that number was reduced to approximately 65% in striatum and 34% in the neocortex of P15 pups, and approximately 26% in striatum and 2% in neocortex of P26 rats. In P60 rats, less than 4% of the damaged neurons in striatum and less than 1% in neocortex were positive for active caspase-3. Western blot analysis demonstrated that the level of inactive caspase-3 in normal forebrain tissue gradually declined from a high level in young pups to very low levels in adult rats. Concomitantly, HI-induced active caspase-3 was reduced from a relatively high level in P7, to moderate levels in P15 and P26, to a barely detectable level in P60 rats. The authors conclude that the involvement of caspase-3 in the pathogenesis of cell death after HI declines during neuronal maturation. The authors hypothesize that caspase-3 may play a major role in cell death in immature neurons but a minor role in cell death in mature neurons after brain injury.
在脑发育过程中研究了半胱天冬酶 -3在缺氧缺血（HI）后细胞死亡中的作用。通过左颈动脉结扎和全身缺氧（8%氧气）相结合的方法，在出生后第7天（P7）、15天（P15）、26天（P26）和60天（P60）的大鼠中产生单侧HI。使用抗活性半胱天冬酶 -3抗体和碘化丙啶，通过高分辨率共聚焦显微镜原位检测半胱天冬酶 -3的激活和细胞死亡，并进行生化分析。在P7幼崽中，活性半胱天冬酶 -3阳性神经元由超过90%的HI损伤纹状体和新皮质神经元组成，但在P15幼崽的纹状体中这一比例降至约65%，在新皮质中降至34%，在P26大鼠的纹状体中约为26%，在新皮质中为2%。在P60大鼠中，纹状体中受损神经元中活性半胱天冬酶 -3阳性的不到4%，新皮质中不到1%。蛋白质印迹分析表明，正常前脑组织中无活性半胱天冬酶 -3的水平从幼崽中的高水平逐渐下降到成年大鼠中的极低水平。同时，HI诱导的活性半胱天冬酶 -3从P7时的相对高水平降至P15和P26时的中等水平，在P60大鼠中降至几乎检测不到的水平。作者得出结论，在神经元成熟过程中，半胱天冬酶 -3在HI后细胞死亡发病机制中的作用下降。作者推测，半胱天冬酶 -3可能在未成熟神经元的细胞死亡中起主要作用，但在脑损伤后成熟神经元的细胞死亡中起次要作用。
