The effects of proteoglycans from different cartilage types on in vitro hydroxyapatite proliferation.

Proteoglycans extracted from nasal and articular cartilages have previously been shown to inhibit hydroxyapatite proliferation in vitro. This study now demonstrates that proteoglycans isolated (dissociatively extracted and reaggregated in vitro) from bovine fetal growth plate and bovine occipital condyle, as well as those from bovine nasal cartilage, all retard hydroxyapatite seeded-growth in vitro. On a weight basis (1 mg/ml), the growth plate proteoglycan preparation had a significantly greater inhibitory effect. The greater inhibitory effect of the growth plate proteoglycans as compared to the other cartilage proteoglycan preparations may be related to the unique properties of the proteoglycans in the growth plate, a tissue that undergoes physiological calcification.