Radiation effects on osteoblasts in vitro - A potential role in osteoradionecrosis

Objective: To evaluate the factors involved in bone remodeling and wound he aling that may be altered by radiation therapy. Design: A prospective, controlled study of biochemical activity in vitro. Subjects: MC3T3-E1 mouse osteoblasts. Interventions: Cells were irradiated at 0, 2, 4, or 6 Gy. Specimens were ha rvested at 1, 7, 14, 28, and 42 days following irradiation for immunohistoc hemical analysis of transforming growth factor beta(1) expression and trans forming growth factor beta(1) type I and II receptor expression. Collagen p roduction was measured at 1, 7, 28, 35, and 49 days after irradiation. The effects of dexamethasone on collagen production and cell proliferation were also examined. Results: Irradiated cells demonstrated decreased cell proliferation and a d ose-dependent, sustained reduction in collagen production when compared wit h control cells. An increase in transforming growth factor beta(1) type I a nd II receptor expression was noted in irradiated cells when compared with controls. Conclusion: Radiation-induced alterations of factors related to bone remode ling and wound healing have a potential role in the pathogenesis of osteora dionecrosis.