Integrated Dental Clinic Program, Faculty of Dentistry, Federal University of Uberlândia, Avenida Pará s/n°, Campus Umuarama, Bloco 4L, Bairro Umuarama, Uberlândia, Minas Gerais, 38.400-902, Brazil.
Department of Periodontology and Oral Implantology, Faculty of Dentistry, Federal University of Uberlândia, Avenida Pará s/nº, Campus Umuarama, Bloco 4L, Bairro Umuarama, Uberlândia, Minas Gerais, 38.400-902, Brazil.
Radiat Oncol. 2020 May 6;15(1):95. doi: 10.1186/s13014-020-01542-2.
Radiotherapy used in tumor treatment compromises vascularization of bone tissue. Hyperbaric oxygenation (HBO) increases oxygen availability and improves vascularization, minimizing the deleterious effects of ionizing radiation (IR). Therefore, the aim of this study was to evaluate HBO therapy effect on bone macroscopy, composition and biomechanical properties after IR damage.
Twenty male Wistar rats weighing 300 ± 20 g (10 weeks of age) were submitted to IR (30 Gy) to the left leg, where the right leg was not irradiated. After 30 days, ten animals were submitted to HBO therapy, which was performed daily for 1 week at 250 kPa for 90-min sessions. All animals were euthanized 37 days after irradiation and the tibia were separated into four groups (n = 10): from animals without HBO - right tibia Non-irradiated (noIRnoHBO) and left tibia Irradiated (IRnoHBO); and from animals with HBO - right tibiae Non-irradiated (noIRHBO) and left tibia Irradiated (IRHBO). The length (proximal-distal) and thickness (anteroposterior and mediolateral) of the tibiae were measured. Biomechanical analysis evaluated flexural strength and stiffness. Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) was used to calculate the amide I ratio, crystallinity index, and matrix to mineral ratios.
In the macroscopic and ATR-FTIR analysis, the IRnoHBO showed lower values of length, thickness and amide I ratio, crystallinity index and matrix to mineral ratios compared to noIRnoHBO (p < 0.03). IRnoHBO showed no statistical difference compared to IRHBO for these analyses (p > 0.05). Biomechanics analysis showed that the IRnoHBO group had lower values of flexural strength and stiffness compared to noIRnoHBO and IRHBO groups (p < 0.04). In addition, the noIRHBO group showed higher value of flexural strength when compared to noIRnoHBO and IRHBO groups (p < 0.02).
The present study concluded that IR arrests bone development, decreases the collagen maturation and mineral deposition process, thus reducing the flexural strength and stiffness bone mechanical parameters. Moreover, HBO therapy minimizes deleterious effects of irradiation on flexural strength and the bone stiffness analysis.
肿瘤治疗中的放射疗法会损害骨组织的血管化。高压氧治疗（HBO）可增加氧气供应并改善血管化，从而最大程度地减少电离辐射（IR）的有害影响。因此，本研究的目的是评估 HBO 治疗对 IR 损伤后骨宏观结构、组成和生物力学特性的影响。
将 20 只雄性 Wistar 大鼠（体重 300±20g，10 周龄）的左腿接受 IR（30Gy）照射，右腿未照射。30 天后，将 10 只动物进行 HBO 治疗，每天进行 1 周，在 250kPa 下进行 90 分钟的治疗。所有动物在照射后 37 天处死，将胫骨分为 4 组（n=10）：未接受 HBO 治疗的右胫骨（无 IR 无 HBO）和左胫骨（IR 无 HBO）；接受 HBO 治疗的右胫骨（无 IR HBO）和左胫骨（IR HBO）。测量胫骨的长度（近端-远端）和厚度（前-后和内-外侧）。生物力学分析评估了弯曲强度和刚度。衰减全反射傅里叶变换红外光谱（ATR-FTIR）用于计算酰胺 I 比、结晶度指数和基质与矿物质比。
在宏观和 ATR-FTIR 分析中，IRnoHBO 的长度、厚度和酰胺 I 比、结晶度指数和基质与矿物质比均低于无 IRnoHBO（p<0.03）。IRnoHBO 与 IRHBO 相比，这些分析无统计学差异（p>0.05）。生物力学分析显示，IRnoHBO 组的弯曲强度和刚度值低于无 IRnoHBO 和 IRHBO 组（p<0.04）。此外，与无 IRnoHBO 和 IRHBO 组相比，无 IRHBO 组的弯曲强度值更高（p<0.02）。
本研究表明，IR 会阻止骨骼发育，减少胶原成熟和矿物质沉积过程，从而降低骨骼机械参数的弯曲强度和刚度。此外，HBO 治疗可最大程度地减少 IR 对弯曲强度和骨骼刚度分析的有害影响。
