Analysis of immediate radiation effects on osteoporotic bone morphology and mechanical properties / Ayuni Amalina Abu Bakar

Introduction: Although bone architecture and its mechanical properties are known to deteriorate after radiotherapy, the effects of radiation on osteoporotic bones in menopause patients have not been fully understood. Therefore, this study investigates the effects of radiation on the osteoporotic femur of menopause-induced mice. Materials and Methods: Ovari ectomy was performed on 38-week-old BALB/c mice (n=6) to induce menopause and osteoporosis, and the animals were allowed to recover for 10 weeks. Then, the mice in the irradiated group were exposed to Caesium-137 Chloride sources at a dose of 30 Gy. After seven days, all mice were euthanised and their femurs were dissected. Micro-computed tomography (μCT Skyscan 1172) was performed on the distal femurs at voxel size of 8 μm in 20-minute scans, and the bones were quantified using a CT-analyser. Thereafter, bone durability was analysed in a three-point bending simulation (ANSYS Workbench software version 2020 R1). Results: μCT analysis showed that irradiated mice had reduced bone volume (-41.65 %), trabecular number (-30.56 %) and trabecular thickness (- 21 %), besides increased trabecular separation (50.95 %) compared with control littermates. The same trend was observed in the cortical bone at the diaphysis region. There was reduction in total area (-1.75 %) and cortical area (-4 %) despite an increase in cortical thickness (10.56 %). Additionally, cortical stiffness and flexural strength was also significantly reduced by -35.06 % and 18 %. Conclusion: The findings show that irradiation can alter the microarchitecture and mechanical properties of bones in an animal model. Hence, targeted therapy strategies should be improved to reduce the deleterious effects on the bone caused by the irradiation.