PROTEOLYTIC-ENZYMES IN EXPERIMENTAL SPINAL-CORD INJURY
PROTEOLYTIC-ENZYMES IN EXPERIMENTAL SPINAL-CORD INJURY
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DOI：
10.1016/0022-510x(86)90149-8
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发表时间：
1986-05-01
影响因子：
4.4
通讯作者：
SMITH, KP
中科院分区：
文献类型：
--
作者：
BANIK, NL;HOGAN, EL;SMITH, KP
大鼠硬膜包埋裸露脊髓，从30 cm处掉下10g体重，造成实验性脊髓损伤。在中性(pH 7.6)和酸性(pH 5.5和3.6)pH下，测定了整个匀浆以及病变(腰椎)和颈部对照节段的胞浆部分的蛋白分解活性。用SDS-PAGE分析底物髓鞘碱性蛋白(MBP)的降解程度来监测酶的活性。伤后24 h，假手术组脊髓组织中性和组织蛋白酶B样活性均低于颈椎自体对照组。中性蛋白酶活性的增加是进行性的，并且比自体对照的增加幅度更大。A 61.5%。+-。3.5 MBP在伤后2 h开始丢失，24 h时增加(78.2%)。3.4)。MBP的丢失与几个小分子多肽的出现相吻合。组织蛋白酶B样酶和组织蛋白酶D的活性在皮损中也有升高，但幅度小于中性蛋白酶。中性蛋白酶和组织蛋白酶B的活性可被亮胃素抑制，而组织蛋白酶D的活性则不受胃抑素的抑制。中性蛋白分解活性的释放是非溶酶体来源的，这为创伤性轴突-髓鞘损伤的机制提出了一个新的假说。
Experimental spinal cord injury was produced in rats by dropping a 10 g weight from 30 cm upon dura-invested exposed spinal cord. Proteolytic activities at neutral (pH 7.6) and acid (pH 5.5 and 3.6) pH were determined in whole homogenate and the cytosolic fraction of the lesion (lumbar) and cervical control segments. The enzyme activity was monitored by SDS-PAGE analsysis of the extent of substrate myelin basic protein (MBP) degradation. Activities (neutral and cathepsin B-like) in the sham-operated spinal cord were lower than those of cervical autologous control at 24 h after injury. The increase in neutral proteinase activity was progressive and greater in the lesion than the autologous control. A 61.5% .+-. 3.5 loss of MBP was observed at 2 h following injury and increased at 24 h (78.2% .+-. 3.4). The loss of MBP coincided with the appearance of several low molecular weight peptides. The cathepsin B-like and cathepsin D activities were also increased in the lesion but to a lesser extent than the neutral proteinase. The neutral proteinase and cathepsin B-like activity were inhibited by leupeptin and not by pepstatin while the converse obtained for cathepsin D activity. The release of neutral proteolytic activity which is nonlysosomal in origin suggests a novel hypothesis for the mechanism of traumatic axon-myelin injury.