Radiation-induced changes in load-sharing and structure-function behavior in murine lumbar vertebrae
Tongge Wu1, Noah B Bonnheim2, Megan M Pendleton1
1Department of Mechanical Engineering, University of California, Berkeley, CA, USA.
Summary
Ionizing radiation exposure reduced trabecular bone volume in mouse lumbar vertebrae, leading to increased reliance on the vertebral cortex for load bearing. This study reveals radiation
Area of Science:
- Biomechanics
- Radiology
- Orthopedics
Background:
- Ionizing radiation is used in medical treatments, but its effects on bone microstructure and mechanical function are not fully understood.
- Understanding radiation's impact on bone is crucial for managing patient outcomes and developing protective strategies.
Purpose of the Study:
- To investigate the biomechanical effects of ionizing radiation on murine lumbar vertebrae microstructure and mechanical function.
- To evaluate changes in vertebral microstructure, whole-bone stiffness, and cortical-trabecular load sharing following radiation exposure.
Main Methods:
- Micro-computed tomography (micro-CT) based finite element analysis was employed.
- Murine lumbar vertebrae (L5) were analyzed 11 days post-exposure to a 5 Gy total dose of ionizing radiation.
- Trabecular and cortical bone microstructure, whole-bone stiffness, and load distribution were quantified and compared between irradiated and control groups.
Main Results:
- Irradiated vertebrae showed significantly reduced trabecular bone volume and altered microstructure (p < 0.001), while cortical bone volume remained unchanged.
- Axial compressive loads were redistributed from the trabecular centrum to the vertebral cortex in irradiated mice, indicated by a higher cortical load-fraction (p = 0.02).
- The structure-function relationship between trabecular bone volume and load fraction differed, suggesting a less biomechanically efficient trabecular network in irradiated vertebrae (p = 0.03).
Conclusions:
- Ionizing radiation decreases trabecular bone volume and compromises the biomechanical efficiency of the vertebral trabecular structure.
- Radiation exposure leads to an increased reliance on the vertebral cortex to resist compressive loads, altering the load-sharing mechanism.
- These findings provide biomechanical insights into radiation-induced structural changes in murine lumbar vertebrae, independent of material property changes.
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