ISSN:
1432-0827
Keywords:
Osteoblasts
;
Collagen
;
Cross-links
;
Calcification
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
,
Physics
Notes:
Summary The early stage of cross-link formation in bone collagen was studied in a cell culture system. An osteogenic cell line that produces and accumulates a remarkably high amount of collagen, and that eventually forms bone-like structures, was used in this study for its time-dependent development of reducible cross-links. It was found that precursors of the cross-link, dehydro-dihydroxynorleucine and dehydro-hydroxynorleucine became detectable as soon as the cells attained a confluent state. They showed maximal amounts at day 3–5 after confluence, but substantially disappeared at day 10 after confluence. In contrast, two characteristic cross-links of bone collagen, dehydrodihydroxylysinonorleucine dehydro-DHLNL and dehydrohydroxylysinonorleucine (dehydro-HLNL), which were present in trace amounts at the stage of cell confluence, gradually increased in amount and reached a plateau at day 10, just when their precursors disappeared. Thus, it was found that there was a time lag of about a week between the maximal formations of precursors and cross-links of bone collagen in this system. The significance of this time lag was interpreted in terms of the minimum essential accumulation of collagen for the precursor-product transition. The ratio of dehydro-DHLNL to dehydro-HLNL was as low as 0.7 at day 3 after confluency, increased to 4.2 at day 20, the period just before mineralization began, and decreased thereafter, suggesting a qualitative change in bone collagen associated with mineralization.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00296780
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