The effect of ascorbic acid on the turnover of collagen in bone in tissue culture

Abstract

Ascorbic acid is required for collagen synthesis but its role in other aspects of collagen metabolism is unclear. Neonatal mouse calvaria were incubated in tissue culture in the presence of 0·05 or 50·0 μg/ml ascorbic acid to determine the effect on bone collagen synthesis, crosslinking and degradation. H3‐proline was added to the culture media to label the collagen newly synthesized in vitro with H3‐hydroxyproline. Ascorbic acid increased the synthesis but descreased the degradation of the H3‐hydroxyproline‐labeled bone collagen. Ascorbate increased the specific activity (CPM H3‐hyp/μg hyp) of the insoluble collagen, with no effect on the acid‐soluble collagen, indicating that the newly synthesized bone matrix was more highly crosslinked. On the other hand, the degradation of the preformed unlabeled collagen appeared to be increased. It was concluded that ascorbic acid increased bone collagen remodeling in vitro by favouring the the accumulation of newly synthesized bone collagen and the removal or degradation of the older preformed material.