Effect of rat brain tissue extracts on osteoblast proliferation and differentiation

Abstract

Purpose: The reason for enhanced fracture healing in traumatic brain injury patients is not clearly understood. It is possible that factors inherent in the brain passing through the blood-brain barrier to the peripheral circulation, or a disruption of central nervous system (CNS) control of the sympathetic nervous system (SNS), stimulates the process of fracture healing. Methods: In this study, we assessed proliferation [using the 3-[4,5-dimethylthiazol-2-yl]-2,5- diphenyltetrazolium bromide (MTT) assay] and differentiation [using alkaline phosphatase (ALP)] in rat osteoblasts incubated with gray matter or other tissue extracts with and without the addition of an α- or β-adrenergic receptor blocker (phentolamine or propranolol). Results: Gray matter extract from normal brain caused a dose-dependent increase in osteoblast proliferation and differentiation. Serum from normal rats enhanced differentiation but not proliferation. Alpha-receptor blockade had no effect on proliferation or differentiation. Beta-receptor blockade caused a partial, but statistically significant, decrease in gray matter stimulation of osteoblast differentiation. Conclusion: The results of this study indicate that gray matter extract from normal brain increases osteoblast proliferation and differentiation and that β receptors may be involved in differentiation under these conditions. © 2011 Springer-Verlag.