Hill I E, Preston E, Monette R, MacManus J P
Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ont.
Brain Res. 1997 Mar 21;751(2):206-16. doi: 10.1016/s0006-8993(96)01403-5.
The objective of this study was to examine the possible role of the cysteine protease cathepsin B (E.C. 3.4.22.1) in the delayed neuronal death in rats subjected to the two-vessel occlusion model of global ischemia. Immunohistochemistry of the hippocampus showed an alteration in the distribution of cathepsin B in CA1 neurons from a lysosomal pattern to a more intense label redistributed into the cytoplasm. This change was not detected until the neurons had become morphologically altered with obvious shrinkage of the cytoplasmic region. Western blotting and enzyme activity measurements of subcellular fractions, including lysosomes and a cell soluble fraction, demonstrated that there was an overall decrease in cathepsin B activity at this time but an increase in the proenzyme form, particularly in the soluble fraction. This was found to be completely different from the marked loss of all forms of cathepsin B in necrotic neurons following decapitation.
本研究的目的是探讨半胱氨酸蛋白酶组织蛋白酶B（E.C. 3.4.22.1）在两血管闭塞性全脑缺血大鼠迟发性神经元死亡中可能发挥的作用。海马的免疫组织化学显示，CA1神经元中组织蛋白酶B的分布发生改变，从溶酶体模式转变为更强烈的标记，重新分布到细胞质中。直到神经元在形态上发生改变，细胞质区域明显收缩时，才检测到这种变化。对包括溶酶体和细胞可溶性部分在内的亚细胞组分进行蛋白质免疫印迹和酶活性测量，结果表明此时组织蛋白酶B的活性总体下降，但酶原形式增加，尤其是在可溶性部分。这与断头后坏死神经元中所有形式的组织蛋白酶B明显丧失的情况完全不同。
