Dynamics of Irradiation Injury to Bone Tissue

Abstract

The dynamic changes after a single dose of 15, 25 or 40 Gy 60Co were followed in a titanium vital microscopic bone chamber which permitted observation of the same tissue compartment for over 2 years. The chamber consists of a hollow screw containing 2 glass rods 100 micron apart. The device was inserted into the cortex of the proximal tibial metaphysis of a rabbit. During a healing period of 4 to 6 weeks the space between the glass rods became filled with bone and vessels and in some cases fat. Once a steady state in bone remodelling had been achieved, the animals were irradiated. Vital microscopy was then performed at regular intervals. Mature bone was relatively radioresistant since remodelling continued at a normal rate. In contrast, immature woven bone remained unlamellarized and in some animals tended to increase in amount. The vascular architecture was largely unaltered, even after 40 Gy. Thrombosis or hemorrhage clearly attributable to irradiation was not noted. Initially, the number of fat cells was reduced but repopulation was later seen in several cases.

Postoperative irradiation after implant placement: A pilot study for prosthetic reconstruction

“…Significantly reduced bone-regenerative capability and reduced implant osseointegration in irradiated dog and human alveolar bone have also been reported 23. The sensitivity to irradiation is higher for immature bone than for mature bone 24. Clinically, postoperative radiation therapy is commonly initiated 14 - 21 days after ablative surgery,10 at which time wound healing is not yet complete.…”

Engineered Fibrin Gels for Parallel Stimulation of Mesenchymal Stem Cell Proangiogenic and Osteogenic Potential

“…42 While effective in eradicating the damaged cells, previous reports confirm that irradiated defects have severely compromised bone healing due to the impairment in number and activity of endothelial and other tissue-forming cells. 43,44 Nussenbaum et al reported that in animals receiving radiation 2 weeks prior to surgery, inlay calvarial bone graft failed to heal at the wound margins by 4 weeks after surgery. 27 With a clinical eye toward healing irradiated bone defects resulting from head and neck cancer, we selected an irradiated bilateral calvarial defect for our animal model.…”

Stem Cell Therapy Remediates Reconstruction of the Craniofacial Skeleton After Radiation Therapy

“…The corrosive impact of these radiationinduced side effects can be unrelenting and their complex management is rarely remedial. Radiation therapy changes the biologic environment of bone, resulting in a severe attenuation of cellularity and fibrosis [4,5], decreased vascular density, obliteration of small blood vessels, poor fracture and soft tissue healing [6][7][8][9], impaired growth [10], and the late devastating complication of osteoradionecrosis. The bone subjected to X-ray radiation therapy (XRT) demonstrates increased bone resorption, decreased osteogenesis, and reduced [11,12] mechanical strength [13] that predisposes the patients to the debilitating problem of late pathologic fractures with disastrous functional consequences [14].…”