[In vivo osteogenic evaluation of titanium implants with strontium loaded nanotubes].

Objective: To evaluate the in vivo osteogenic activity of titanium implants with strontium loaded TiO2 nanotubes (NTSr). Methods: The strontium loaded titanium nanotubes were formed on pure titanium implants through anodization and hydrothermal treatment, and the unmodified titanium (Control) and sheer TiO2 nanotubes (NT) were set to be control groups and treatment group. Inductively coupled plasma mass spectrometry (ICP-MS) was used to evaluate the Sr release at 28 days. Field emission scanning electron microscopes (FE-SEM) was used to view the micro-topography, atomic force microscope was used to exam the surface roughness, and nano-indenter was used to evaluate the hardness of three groups (n=3). Three groups of implant samples were inserted into the distal femoral metaphysis of New Zealand rabbits (n=4 at each time point). After 4 weeks and 12 weeks, samples were harvested. Micro-CT scanning, immunofluorescent and histological examinations were carried out. Results: The strontium ions could be released slowly for at least 28 days [the Sr concentration at 28 Day was (2.6±1.5) ng/ml]. NTSr coating exhibited a nanoscale tube array (the diameter was about 70 nm), and the surface roughness of implant was increased with the nanobube coating [Control (34.8±5.3) nm, NT (66.2±4.3) nm, NTSr (85.7±10.6) nm, F=37.59, P<0.001]. The surface roughness (Ra) of NT and NTSr groups was higher than the control group (P<0.05). Comparing to Control implants, NTSr implants exhibited a better osteogenic ability [the bone volume/total volume (BV/TV) value was Control (24.7±1.1)% vs. NTSr (37.7±1.9)% at 4 weeks (P<0.05), and Control (40.7±0.9)% vs. NTSr (51.9±2.1)% at 12 weeks (P<0.05)]. The fluorescent examination revealed that NTSr coating can also accelerated the generation of new bone tissue (bone tissue area% labelled by alizarin red at day 7 was Control (19.2±2.9)% vs. NT (35.4±3.7)% vs. NTSr (40.9±0.9)% (F=42.74, P<0.01). The results in the NT and NTSr group were statistically higher than that in the control group (P<0.05). Conclusions: The strontium loaded TiO2 nanotubes can enhance new bone formation around titanium implants.目的： 通过动物实验探讨载锶纳米管化纯钛种植体的体内成骨性能。 方法： 使用阳极氧化和水热处理的方式在纯钛种植体表面构建载锶纳米管涂层（载锶纳米管组），并制备单纯纳米管化种植体（纳米管组）、未处理的光滑纯钛种植体（对照组）。用电感耦合等离子体质谱检测载锶纳米管组种植体第1~28天锶元素释放量。使用扫描电镜观察各组种植体表面形貌，用原子力显微镜检测各组种植体表面粗糙度，并用纳米压痕仪检测各组种植体硬度（每种检测每组3枚种植体）。将3组种植体植入兔股骨骨骺端并于术后4、12周取材（每组每个时间点4枚种植体），通过显微CT、免疫荧光、组织学切片进行组织学评价。 结果： 载锶纳米管组种植体锶元素第28天的释放量为（2.6±1.5）ng/ml。载锶纳米管组种植体表面形成管状阵列样形貌（纳米管管径约70 nm）。对照组、纳米管组、载锶纳米管组种植体表面粗糙度（Ra值）分别为（34.8±5.3）、（66.2±4.3）、（85.7±10.6）nm（F=37.59，P<0.001），纳米管组和载锶纳米管组表面粗糙度均显著大于对照组（P<0.05）。术后4和12周载锶纳米管组骨体积/总体积［分别为（37.7±1.9）%和（51.9±2.1）%］比对照组相同时间点［（24.7±1.1）%和（40.7±0.9）%］均显著增加（P<0.05）；纳米管组和载锶纳米管组种植术后第7天茜素红标记的新生骨组织占总标记骨组织百分比［分别为（35.4±3.7）%和（40.9±0.9）%］均显著大于对照组［（19.2±2.9）%］（P<0.05），即载锶纳米管化提升了种植体周围早期再生骨组织占总再生骨组织的百分比。 结论： 载锶纳米管化可提升种植体周围组织的新骨形成能力。.