Human bone cell cultures in biocompatibility testing. Part II: effect of ascorbic acid, beta-glycerophosphate and dexamethasone on osteoblastic differentiation

This work analyses the proliferation/differentiation behaviour of human bon e marrow cells cultured in alpha-minimum essential medium supplemented with 10% foetal bovine serum (standard medium) and in the presence of ascorbic acid (AA, 50 mu g ml(-1)), beta-glycerophosphate (beta GP, 10 mmol) and dex amethasone (Dex, 10 nmol) under selected experimental conditions. Cultures were compared concerning cell morphology, cell growth, ALP activity and abi lity to form calcium phosphate deposits. Cells growing in the various exper imental conditions proliferated gradually with the incubation time and pres ented high ALP activity. Cultures grown in standard medium and in the prese nce of either AA or Dex failed to form calcium phosphate deposits. Cultures grown in the presence of beta GP, beta GP + AA and beta GP + AA + Dex, i.e . in the presence of a source of phosphate ions, showed the formation of a mineralised extracellular matrix. The presence of Dex resulted in a signifi cant induction in the ALP activity and ability to form mineral deposits. Th e behaviour of the various cell cultures is in agreement with previous stud ies stating a reciprocal and functionally coupled relationship between prol iferation and differentiation, i.e. cultures grown in a medium containing b eta GP presented a less proliferative but more differentiated osteoblastic cell population, as compared to cultures lacking the mineralisation process . (C) 2000 Elsevier Science Ltd. All rights reserved.