Anorganic bovine bone supports osteoblastic cell attachment and proliferation

Background: It was the aim of these studies to examine the ability of an anorganic bovine bone matrix material as an alternative to autogenous bone grafts and demineralized cadaver bone to support the attachment, spreading, and proliferation of isolated osteoblastic cells, Methods: Primary culture osteoblastic cells were isolated from neonatal rat calvaria by sequential collagenase digestion. In the attachment studies, cells which had been labeled with H-3-leucine were incubated with the matrix material in sterile microfuge tubes for 15, 90, or 180 minutes or 24 hours. The attached cells were released and the radioactivity measured by liquid scintillation spectrometry. In the proliferation experiments, the cells were cultured with the matrix material for 24 hours and H-3-thymidine was added during the last 2 hours of the incubation. The cells were released and the radioactivity measured by liquid scintillation spectrometry. Scanning electron microscopy (SEM) was employed to observe osteoblastic cell interaction with the anorganic bone matrix. In these studies the cells were seeded on the bone graft material, then the material was removed and processed for SEM after 30, 60 or 120 minutes, or 24 or 48 hours. Results: The cells attached to the matrix material in a time-dependent manner. There were significantly (P < 0.05) more cells attached after 180 minutes than after the 15 and 90 minute incubations. The matrix material also supported proliferation of the attached osteoblastic cells. Cells seeded onto 100 mg of anorganic bovine bone resulted in significantly (P <0.05) more measurable proliferation than cells seeded onto 10 mg of material. The cells appeared to be round as they attached, then flatten and spread over time. There was also evidence of cellular processes extending into the pores of the material. Conclusions: These results demonstrate that this anorganic bovine bone graft material is able to support the attachment and proliferation of osteoblastic cells.