The effect of ascorbic acid on growth and synthesis of matrix components by cultured chick embryo chondrocytes

Fifty μg/ml ascorbic acid was found to accelerate the growth of logarithmically growing chick embryo sternal chondrocytes in cell culture. Differences in the number of cells between control and ascorbate‐treated cultures were apparent by the fourth day of treatment when a 58% increase in the number of cells and a 35% increase in protein per culture were observed in ascorbate‐treated cultures. Under these conditions, the cell size and protein content per cell was reduced in ascorbate‐treated cultures. Collagen synthesis, which was measured by the amount of collagenase‐sensitive counts released from 3 H‐proline labeled protein, was increased by 116% over controls after 24 hours of ascorbate treatment. Observations with scanning and transmission electron microscopy are consistent with the idea that ascorbate has a much greater effect on collagen secretion and demonstrate an ascorbate‐mediated change in matrix morphology. 35 S incorporation into hyaluronidase‐sensitive or cetylpyridinium chloride precipitates was accelerated by 57% by 24 hours of ascorbate treatment whereas two, four and six days of treatment caused decreases in this parameter of 19%, 57% and 35%, respectively. This effect was dependent on cell density. 35 S incorporation probably reflects synthesis of new glycosaminoglycan similar results were observed when either 35 S or 14 C‐glucose incorporation was monitored. An effect of ascorbate on both collagen and glycosaminoglycan synthesis is consistent with the possibility that collagen and glycosaminoglycan synthesis can be coregulated under some circumstances.