Priscilla Barbosa Ferreira Soares1, Carlos José Soares2, Pedro Henrique Justino Oliveira Limirio3, Rainde Naiara Rezende de Jesus4, Paula Dechichi5, Rubens Spin-Neto6, Darceny Zanetta-Barbosa4. 1. Department of Periodontology and Implantology, School of Dentistry, Federal University of Uberlândia, Avenida Pará s/n°, Campus Umuarama, Bloco 4L, Bairro Umuarama, Uberlândia, Minas Gerais, 38400-902, Brazil. pbfsoares@yahoo.com.br. 2. Department of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlândia, Avenida Pará s/n°, Campus Umuarama, Bloco 4L, Bairro Umuarama, Uberlândia, Minas Gerais, 38400-902, Brazil. 3. Department of Periodontology and Implantology, School of Dentistry, Federal University of Uberlândia, Avenida Pará s/n°, Campus Umuarama, Bloco 4L, Bairro Umuarama, Uberlândia, Minas Gerais, 38400-902, Brazil. 4. Department of Oral and Maxillofacial Surgery, School of Dentistry, Federal University of Uberlândia, Avenida Pará s/n°, Campus Umuarama, Bloco 4T, Bairro Umuarama, Uberlândia, Minas Gerais, 38400-902, Brazil. 5. Institute of Biomedical Sciences, Federal University of Uberlândia, Avenida Pará 1720, Campus Umuarama, Bloco 2B, Bairro Umuarama, Uberlândia, Minas Gerais, 38400-902, Brazil. 6. Department of Dentistry and Oral Health, Department of Oral Radiology, Aarhus University, Vennelyst Boulevard 9, Building 1613, 130, 8000, Aarhus C, Denmark.
Abstract
OBJECTIVES: This study aimed to evaluate the effects of radiotherapy on biomechanical, histomorphometric, and microstructural characteristics of bone, in diverse periods, compared with intact bone tissue. MATERIALS AND METHODS: Eighteen adult male New Zealand rabbits were treated with a single radiation dose of 30 Gy. The animals were randomly divided into six groups: NoIr, control group, no radiation, and five irradiated groups sacrificed after 24 h (Ir24h), 7 (Ir7d), 14 (Ir14d), 21 (Ir21d), and 28 (Ir28d) days. After these periods, the animals were sacrificed and their tibias (n = 6) evaluated using three-point bending test to calculate the ultimate force, work to failure, and bone stiffness. Dynamic indentation test was used to quantify Vickers hardness and elasticity modulus of bone tissue. Micro-CT was used to analyze the cortical volume (CtV), cortical thickness (CtTh), and porosity (Ct.Po). Histomorphometric assessment was based on the lacunarity of bone tissue. Data were analyzed using one-way ANOVA and Kruskal-Wallis tests followed by Tukey, Dunnet, and Dunn's post-tests (P < 0.05). RESULTS: The ultimate force, work to failure, stiffness, elastic modulus, and Vickers hardness values of irradiated bone were significantly lower that non-irradiated bone. Irradiated bone showed significantly lower CtTh and CtV values and higher CtPo than non-irradiated bone. No significant difference was found for lacunarity between non-irradiated bone and irradiated bone. CONCLUSIONS: Ionizing radiation decreases normal anisotropy on microarchitecture of cortical bone, and increases bone fragility compared with non-irradiated bone. Further, these changes were seen after longer periods (e.g., 14 and 21 days), and not immediately after radiation therapy. CLINICAL RELEVANCE: The radiotherapy reduces bone mechanical properties and the normal structure of organic and inorganic bone matrix. For studying the protocols to protect the radiotherapy effect using rabbit model, the use of the sacrificing period between 14 and 21 days is recommended.
OBJECTIVES: This study aimed to evaluate the effects of radiotherapy on biomechanical, histomorphometric, and microstructural characteristics of bone, in diverse periods, compared with intact bone tissue. MATERIALS AND METHODS: Eighteen adult male New Zealand rabbits were treated with a single radiation dose of 30 Gy. The animals were randomly divided into six groups: NoIr, control group, no radiation, and five irradiated groups sacrificed after 24 h (Ir24h), 7 (Ir7d), 14 (Ir14d), 21 (Ir21d), and 28 (Ir28d) days. After these periods, the animals were sacrificed and their tibias (n = 6) evaluated using three-point bending test to calculate the ultimate force, work to failure, and bone stiffness. Dynamic indentation test was used to quantify Vickers hardness and elasticity modulus of bone tissue. Micro-CT was used to analyze the cortical volume (CtV), cortical thickness (CtTh), and porosity (Ct.Po). Histomorphometric assessment was based on the lacunarity of bone tissue. Data were analyzed using one-way ANOVA and Kruskal-Wallis tests followed by Tukey, Dunnet, and Dunn's post-tests (P < 0.05). RESULTS: The ultimate force, work to failure, stiffness, elastic modulus, and Vickers hardness values of irradiated bone were significantly lower that non-irradiated bone. Irradiated bone showed significantly lower CtTh and CtV values and higher CtPo than non-irradiated bone. No significant difference was found for lacunarity between non-irradiated bone and irradiated bone. CONCLUSIONS:Ionizing radiation decreases normal anisotropy on microarchitecture of cortical bone, and increases bone fragility compared with non-irradiated bone. Further, these changes were seen after longer periods (e.g., 14 and 21 days), and not immediately after radiation therapy. CLINICAL RELEVANCE: The radiotherapy reduces bone mechanical properties and the normal structure of organic and inorganic bone matrix. For studying the protocols to protect the radiotherapy effect using rabbit model, the use of the sacrificing period between 14 and 21 days is recommended.
Authors: Ayuni Amalina Abu Bakar; Noor Shafini Mohamad; Mohd Hafizi Mahmud; Hairil Rashmizal Abdul Razak; Ann Erynna Lema Thomas Sudin; Solehuddin Shuib Journal: Biomed Res Int Date: 2022-06-06 Impact factor: 3.246