Effects of colchicine on endocytosis and cellular inactivation of horseradish peroxidase in cultured chondrocytes
Effects of colchicine on endocytosis and cellular inactivation of horseradish peroxidase in cultured chondrocytes
复制标题
秋水仙碱对培养软骨细胞辣根过氧化物酶内吞作用和细胞失活的影响
作者：
A. Piasek;J. Thyberg
以辣根过氧化物酶(HRP)为标记物，研究了微管干扰药物对鸡胚软骨细胞摄取外源物质和细胞失活的影响。HRP通过液体内吞作用被摄取，随后细胞内酶活性随时间呈指数下降。细胞化学显示，HRP的反应产物位于靠近高尔基复合体的小泡中。秋水仙碱和长春花碱导致细胞质微管消失和高尔基复合体解体，细胞对HRP的摄取减少到对照组的一半左右。另一方面，Lumicolchicine使细胞精细结构和HRP摄取未受影响。这些结果表明，微管在培养软骨细胞的液体内吞过程中具有相当重要的作用，但其确切机制仍有待阐明。秋水仙碱或长春花碱不影响细胞内HRP的失活率。用胶体二氧化钍和HRP进行的双标记实验同样表明，内吞囊泡和溶酶体的融合不依赖于完整的微管。用秋水仙碱或长春花碱处理后，三种溶酶体酶的总比活力变化很小或根本没有变化。因此，在培养的软骨细胞中，微管组织似乎不太可能在溶酶体酶的产生或降解中发挥重要作用。
Horseradish peroxidase (HRP) was used as a marker to study the effects of microtubule-disruptive drugs on uptake and cellular inactivation of exogenous material in cultures of embryonic chick chondrocytes. HRP was ingested by fluid endocytosis, and intracellular enzyme activity subsequently diminished exponentially with time. Cytochemically, reaction product for HRP was found in vesicles often located close to the dictyosomes of the Golgi complex. Colchicine and vinblastine caused disappearance of cytoplasmic microtubules and disorganization of the Golgi complex with concomitant reduction in the cellular uptake of HRP to about half of that in the controls. Lumicolchicine, on the other hand, left cell fine structure and HRP uptake unaffected. These results indicate that microtubules are of considerable importance in the process of fluid endocytosis in cultured chondrocytes although the exact mechanism remains to be elucidated. The rate of intracellular inactivation of ingested HRP was not affected by colchicine or vinblastine. Double-labeling experiments with colloidal thorium dioxide and HRP likewise indicated that fusion of endocytic vesicles and lysosomes is not dependent on intact microtubules. The total specific activities of the three lysosomal enzymes examined were weakly or not at all changed by treatment of the cultures with colchicine or vinblastine. It therefore seems unlikely that microtubular organization plays an important role in the production or degradation of lysosomal enzymes in cultured chondrocytes.