BACKGROUND Numerous studies have reported the beneficial effects of strontium on bone growth, particularly by stimulating osteoblast proliferation and differentiation. Thus, strontium release around implants has been suggested as one possible strategy to enhance implant osseointegration. AIM This study aimed to evaluate whether the local release of strontium ranelate (Sr-ranelate) from implants coated with mesoporous titania could improve bone formation around implants in an animal model. MATERIALS AND METHODS Mesoporous titania (MT) thin coatings were formed utilizing the evaporation induced self-assembly (EISA) method using Pluronic (P123) with or without the addition of poly propylene glycol (PPG) to create materials with two different pore sizes. The MT was deposited on disks and mini-screws, both made of cp Ti grade IV. Scanning electron microscopy (SEM) was performed to characterize the MT using a Leo Ultra55 FEG instrument (Zeiss, Oberkochen, Germany). The MT was loaded with Sr-ranelate using soaking and the drug uptake and release kinetics to and from the surfaces were evaluated using quartz crystal microbalance with dissipation monitoring (QCM-D) utilizing a Q-sense E4 instrument. For the in vivo experiment, 24 adult rats were analyzed at two time points of implant healing (2 and 6 weeks). Titanium implants shaped as mini screws were coated with MT films and divided into two groups; supplied with Sr-ranelate (test group) and without Sr-ranelate (control group). Four implants (both test and control) were inserted in the tibia of each rat. The in vivo study was evaluated using histomorphometric analyses of the implant/bone interphase using optical microscopy. RESULTS SEM images showed the successful formation of evenly distributed MT films covering the entire surface with pore sizes of 6 and 7.2 nm, respectively. The QCM-D analysis revealed an absorption of 3300 ng/cm2 of Sr-ranelate on the 7.2 nm MT, which was about 3 times more than the observed amount on the 6 nm MT (1200 ng/cm2). Both groups showed sustained release of Sr-ranelate from MT coated disks. The histomorphometric analysis revealed no significant differences in bone implant contact (BIC) and bone area (BA) between the implants with Sr-ranelate and implants in the control groups after 2 and 6 weeks of healing (BIC with a p-value of 0.43 after 2 weeks and 0.172 after 6 weeks; BA with a p-value of 0.503 after 2 weeks, and 0.088 after 6 weeks). The mean BIC and BA values within the same group showed significant increase among all groups between 2 and 6 weeks. CONCLUSION This study could not confirm any positive effects of Sr-ranelate on implant osseointegration.

中文翻译：

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雷奈酸锶从大鼠植入物表面局部释放的骨整合作用。

背景技术大量研究报道了锶对骨生长的有益作用，特别是通过刺激成骨细胞的增殖和分化。因此，已提出锶在植入物周围的释放是增强植入物骨整合的一种可能策略。目的本研究旨在评估在动物模型中，雷奈酸锶（Sr-ranelate）从涂有介孔二氧化钛的植入物中的局部释放是否可以改善植入物周围的骨形成。材料与方法使用Pluronic（P123）或不添加聚丙二醇（PPG）的蒸发诱导自组装（EISA）方法形成中孔二氧化钛（MT）薄涂层，以创建具有两种不同孔径的材料。MT放置在均由cp Ti IV级制成的磁盘和微型螺钉上。使用Leo Ultra55 FEG仪器（Zeiss，Oberkochen，德国）进行扫描电子显微镜（SEM）表征MT。使用浸泡法将MT装载有Sr-ranelate，并使用Q-ensen E4仪器通过带有耗散监测（QCM-D）的石英晶体微量天平评估药物在表面的吸收和释放动力学。对于体内实验，在植入物愈合的两个时间点（2周和6周）分析了24只成年大鼠。形状为微型螺钉的钛植入物涂有MT膜，并分为两组；第二组为钛合金。提供有Sr-ranelate（测试组）和不含Sr-ranelate（对照组）。在每只大鼠的胫骨中插入四个植入物（测试和对照）。通过使用光学显微镜对植入物/骨间相进行组织形态计量学分析评估了体内研究。结果SEM图像显示成功形成了均匀分布的MT膜，覆盖了整个表面，孔径分别为6和7.2 nm。QCM-D分析显示，在7.2 nm MT上吸收了3300 ng / cm2的Sr-ranelate，这是在6 nm MT（1200 ng / cm2）上观察到的吸收量的三倍。两组均显示MT涂层盘中Sr-ranelate持续释放。组织形态计量学分析显示，愈合2周和6周后，含Sr-ranelate的植入物与对照组的植入物之间的骨植入物接触（BIC）和骨面积（BA）均无显着差异（BIC的p值为0.43； 2周，6周后为0.172； BA的p值在2周后为0.503，在6周后为0.088）。同一组内的平均BIC和BA值在2至6周之间显示出所有组之间的显着增加。结论这项研究不能证实Sr-ranelate对植入物骨整合有任何积极作用。