To clarify the role of vitamins D and C in chondrocyte hypertrophy of craniofacial cartilage, we have studied cultured chondrocytes from rabbit mandibular condylar cartilage (MCC), sphenooccipital synchondrosis (SOS) and nasal septal cartilage (NSC) under conditions in which these cells mature into hypertrophic chondrocytes. In cultures of MCC- and SOS-chondrocytes, alkaline phosphatase (ALPase) activity started to increase on day 9 at confluence and the cessation of cell division, and reached a maximum on day 18. The degree of the increase of ALPase activity on day 18 was higher in MCC-chondrocytes than in SOS-chondrocytes. ALPase activity was very low level in NSC- and CGC-chondrocytes. Ascorbic acid induced a marked increase in ALPase activity in MCC-, SOS-, NSC- and CGC-chondrocytes. The ALPase activities in MCC- and SOS-chondrocytes with 50 micrograms/ml ascorbic acid were 2.5-times those in its absence. Those in NSC- and CGC-chondrocytes were 10 times and 20 times, respectively. When chondrocytes were cultured with 10% charcoal-treated serum, ALPase activity decreased less than that in cultures with 10% normal serum in MCC-, SOS-, NSC- and CGC-chondrocytes. Treatment of 1,25-(OH)2D3 for 9 days from days 4 to 13 in MCC-chondrocytes and for 14 days from days 4 to 18 in SOS-, NSC- and CGC-chondrocytes inhibited ALPase activity dose-dependently at the concentrations of 10(-12) M to 10(-8) M in MCC- chondrocytes, 10(-10) M to 10(-8) M in SOS- and CGC-chondrocytes, 10(-11) M to 10(-9) M in NSC-chondrocytes. These findings suggest that 1,25-(OH)2D3 and ascorbic acid may be involved in the control of cartilage growth and terminal differentiation.
|Number of pages||8|
|Journal||The Journal of Osaka University Dental School|
|Publication status||Published - 1992 Dec|