Data from: Enhancement of apoptosis by titanium alloy internal fixations during microwave treatments for fractures: an animal study

Objective: Microwaves are used in one method of physical therapy and can increase muscle tissue temperature which is useful for improving muscle, tendon and bone injuries. In the study, we sought to determine whether titanium alloy internal fixations influence apoptosis in tissues subjected to microwave treatments at 2,450 MHz and 40 W during the healing of fractures because this issue is not yet fully understood. Methods: In this study, titanium alloy internal fixations were used to treat 3.0-mm transverse osteotomies in the middle of New Zealand rabbits’ femurs. After the operation, 30-day microwave treatments were applied to the 3.0 mm transverse osteotomies 3 days after the operation. The changes in the temperatures of the muscle tissues in front of the implants or the 3.0 mm transverse osteotomies were measured during the microwave treatments. To characterize the effects of titanium alloy internal fixations on apoptosis in the muscles after microwave treatment, we performed TUNEL assays, fluorescent real-time (quantitative) PCR, western blotting analyses, reactive oxygen species (ROS) detection and transmission electron microscopy examinations. Results: The temperatures were markedly increased in the animals with the titanium alloy implants. Apoptosis in the muscle cells of the implanted group was significantly more extensive than that in the non-implanted control group at different time points. Transmission electron microscopy examinations of the skeletal muscles of the implanted groups revealed muscular mitochondrial swelling, vacuolization. ROS, Bax and Hsp70 were up-regulated, and Bcl-2 was down-regulated in the implanted group. Conclusion: Our results suggest that titanium alloy internal fixations caused greater muscular tissue cell apoptosis following 2,450 MHz, 40 W microwave treatments in this rabbit femur fracture models.

研究目的：微波是物理治疗的常用手段之一，可提升肌肉组织温度，对改善肌肉、肌腱及骨损伤具有积极作用。本研究旨在探究2450MHz、40W的微波照射下，钛合金内固定装置是否会影响骨折愈合过程中受照射组织的细胞凋亡情况——该问题目前尚未得到充分阐明。
研究方法：本研究选取新西兰兔股骨中段构建3.0mm横行截骨模型，并采用钛合金内固定装置进行固定。术后第3天起，对截骨部位进行为期30天的微波照射治疗。照射过程中，分别检测植入物前方肌肉组织及截骨部位的温度变化。为表征钛合金内固定装置对微波照射后肌肉组织细胞凋亡的影响，本研究采用了末端脱氧核苷酸转移酶介导的dUTP缺口末端标记（TUNEL）检测、荧光实时（定量）聚合酶链式反应（PCR）、蛋白质印迹（Western blotting）分析、活性氧（ROS）检测以及透射电子显微镜检查等实验手段。
研究结果：植入钛合金内固定装置的实验动物，其肌肉组织温度显著升高。在不同时间节点，植入组肌肉细胞的细胞凋亡程度均显著高于未植入内固定装置的对照组。对植入组骨骼肌的透射电子显微镜观察显示，肌线粒体出现肿胀、空泡化现象。植入组的活性氧（ROS）、Bax及热休克蛋白70（Hsp70）表达上调，而B细胞淋巴瘤-2（Bcl-2）表达下调。
研究结论：本研究结果表明，在新西兰兔股骨骨折模型中，经2450MHz、40W微波照射后，钛合金内固定装置会导致肌肉组织细胞凋亡程度进一步加剧。