CHARACTERISTICS AND CULTURE OF OSTEOBLASTS DERIVED FROM AVIAN LONG-BONE

A method is presented for isolating primary osteoblasts from the perio steal surface of chick tibia. The culture system identified supports b oth cell proliferation and phenotype retention. Cell numbers increased 8-fold in Week 1 and 20-fold over a total of 12 days. Well-establishe d osteoblast markers, alkaline phosphatase staining, gamma-carboxyglut amic acid, osteocalcin, type I collagen, and parathyroid hormone bindi ng were detected. Osteocalcin, gamma-carboxyglutamic acid, and type I collagen were present on culture Day 4, and were increased in amount b y Day 8, but were similar to the earlier level on Day 12, suggesting t hat the phenotype may revert to a less differentiated state by 12 days in culture. Alkaline phosphatase staining was intense at all three as say times, however. During the last 4 days of the 12-day culture perio d, proliferation rates were higher than in the previous 8 days.