Boskey A L, Maresca M, Armstrong A L, Ehrlich M G
Laboratory for Ultrastructural Biochemistry, Hospital for Special Surgery, New York, New York 10021.
J Orthop Res. 1992 May;10(3):313-9. doi: 10.1002/jor.1100100302.
In vitro, cartilage proteoglycans (PGs) are effective inhibitors of hydroxyapatite formation and growth. Their inhibitory ability decreases with decreasing PG size and charge density. It has been suggested that the enzyme-mediated alteration in the size and conformation of PGs in the growth plate may similarly facilitate the calcification process. In this study, a gelatin gel system was used to monitor hydroxyapatite formation and growth in the presence of proteoglycan aggregates, before and after enzyme treatment. To reproduce the physeal degradation cascade, an enzyme preparation was used that contained all of the growth plate enzymes. At a concentration of 500 micrograms/ml, the untreated proteoglycan aggregates reduced the amount of mineral formed by 30%. When the aggregates were treated with the heat-inactivated enzyme, the same extent of inhibition was found. In contrast, treating the aggregates with the crude growth plate enzyme preparation removed all the inhibitory ability, such that 500 micrograms/ml of proteoglycan preparation yielded 10% more mineral than the controls. Treatment of the aggregates with chondroitinase ABC and trypsin, similarly removed all the inhibitory ability. These data, suggest that enzymatic degradation of proteoglycans may contribute to the regulation of growth plate calcification.
在体外，软骨蛋白聚糖（PGs）是羟基磷灰石形成和生长的有效抑制剂。它们的抑制能力随着PG大小和电荷密度的降低而降低。有人提出，生长板中酶介导的PGs大小和构象的改变可能同样促进钙化过程。在本研究中，使用明胶凝胶系统监测酶处理前后蛋白聚糖聚集体存在下羟基磷灰石的形成和生长。为了重现骨骺降解级联反应，使用了一种包含所有生长板酶的酶制剂。在浓度为500微克/毫升时，未处理的蛋白聚糖聚集体使形成的矿物质数量减少了30%。当聚集体用热灭活酶处理时，发现了相同程度的抑制作用。相比之下，用粗制生长板酶制剂处理聚集体消除了所有抑制能力，因此500微克/毫升的蛋白聚糖制剂产生的矿物质比对照组多10%。用软骨素酶ABC和胰蛋白酶处理聚集体同样消除了所有抑制能力。这些数据表明，蛋白聚糖的酶促降解可能有助于生长板钙化的调节。
