Olbricht C J, Cannon J K, Tisher C C
Laboratory of Experimental Morphology, University of Florida College of Medicine, Gainesville.
Kidney Int. 1987 Sep;32(3):354-61. doi: 10.1038/ki.1987.217.
The intralysosomal proteinases, cathepsins B and L, were measured in microdissected segments of rat nephrons following a single injection of puromycin aminonucleoside (PAN). Z-Phenylalanyl-arginine-7-amido-4-methylcoumarin served as substrate. Enzyme activities, proteinuria, creatinine clearance and renal morphology were determined at specific time intervals following induction of PAN nephrosis. During the first three days following PAN injection, enzyme activities in S2 and S3 segments, protein excretion, creatinine clearance and appearance of the renal parenchyma resembled control animals. The enzyme activity in S1 segments was slightly decreased, but returned to control levels at day six after injection. Days four through eight post-PAN injection were characterized by a dramatic increase in protein excretion and an increase in cathepsin B and L activity in S2 and S3 segments of the proximal tubule. During days 9 through 15 enzyme activity decreased significantly in S2 segments despite continued proteinuria. Overt necrosis and cell injury were seen in the proximal tubule and probably account for the decrease in proteolytic activity. After day 15 following PAN injection, the level of proteinuria decreased, restoration of cathepsin activities occurred and a histopathologic picture of healing was present. The data suggest a positive relationship exists between stimulation of cathepsin B and L activity in S2 and S3 segments of the proximal tubule and increased protein filtration in PAN nephrosis. The increased enzyme activity reflects enhancement of the proteolytic capacity of the lysosomal system that is necessary for increased protein catabolism.
在单次注射嘌呤霉素氨基核苷（PAN）后，对大鼠肾单位的显微切割节段中的溶酶体内蛋白酶组织蛋白酶B和L进行了测定。Z-苯丙氨酰-精氨酸-7-氨基-4-甲基香豆素用作底物。在诱导PAN肾病后的特定时间间隔测定酶活性、蛋白尿、肌酐清除率和肾脏形态。在注射PAN后的头三天，S2和S3节段的酶活性、蛋白质排泄、肌酐清除率以及肾实质外观与对照动物相似。S1节段的酶活性略有下降，但在注射后第六天恢复到对照水平。PAN注射后第四天至第八天的特征是蛋白质排泄急剧增加，近端小管S2和S3节段中的组织蛋白酶B和L活性增加。在第9天至第15天期间，尽管蛋白尿持续存在，但S2节段的酶活性显著下降。在近端小管中可见明显的坏死和细胞损伤，这可能是蛋白水解活性降低的原因。在PAN注射后第15天之后，蛋白尿水平下降，组织蛋白酶活性恢复，出现愈合的组织病理学图像。数据表明，近端小管S2和S3节段中组织蛋白酶B和L活性的刺激与PAN肾病中蛋白质滤过增加之间存在正相关关系。酶活性增加反映了溶酶体系统蛋白水解能力的增强，这是蛋白质分解代谢增加所必需的。
