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

Objective: To evaluate the factors involved in bone remodeling and wound healing 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 harvested at 1, 7, 14, 28, and 42 days following irradiation for immunohistochemical analysis of transforming growth factor β₁ expression and transforming growth factor β₁ type I and II receptor expression. Collagen production 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 dose-dependent, sustained reduction in collagen production when compared with control cells. An increase in transforming growth factor β₁ type I and II receptor expression was noted in irradiated cells when compared with controls. Conclusion: Radiation-induced alterations of factors related to bone remodeling and wound healing have a potential role in the pathogenesis of osteoradionecrosis.