Biodegradable materials based on magnesium alloys have a huge potential for bone fracture fixation devices due to their adequate mechanical properties and biocompatibility. However, their fast degradation and the consequent liberation of hydrogen gas at the initial stages of implantation is the major limitation for their use. In this study, the AZ91D magnesium alloy was surface treated by an environment-friendly, nontoxic, and low-cost anodizing process and the early in vivo response was studied in a rat transcortical model. Adequate maturation of woven bone around implants—detected at day 7 post implantation—to lamellar bone was observed from day 15. Lamellar bone after 15 and 30 days of implantation presented similar volume, mineralization pattern, mineral to protein content, and estimated bone maturity between anodized AZ91D and polylactic acid (control) implants. Histology observation showed neither release of hydrogen bubbles in the region closed to the anodized AZ91D implant nor systemic effects on liver, kidney, and spleen. Thus, anodizing of AZ91D in the conditions stated here induced an adequate short-term in vivo response, which postulates their use as potential biodegradable fracture fixation devices for bone healing.

中文翻译：

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阳极氧化镁合金作为骨骨折固定装置的可生物降解材料的短期体内反应

基于镁合金的可生物降解材料由于其足够的机械性能和生物相容性，在骨折固定装置方面具有巨大的潜力。然而，它们的快速降解和随后在注入初始阶段释放的氢气是它们使用的主要限制。在本研究中，AZ91D 镁合金采用环保、无毒、低成本的阳极氧化工艺进行表面处理，并在大鼠经皮层模型中研究了体内早期反应。从第 15 天观察到植入物周围的编织骨（在植入后第 7 天检测到）到板层骨的充分成熟。植入 15 天和 30 天后的板层骨呈现出相似的体积、矿化模式、矿物质与蛋白质含量、以及阳极氧化 AZ91D 和聚乳酸（对照）植入物之间的估计骨成熟度。组织学观察显示在靠近阳极氧化 AZ91D 植入物的区域中既没有释放氢气泡，也没有对肝脏、肾脏和脾脏产生全身影响。因此，在此处所述的条件下对 AZ91D 进行阳极氧化会引起足够的短期体内反应，这表明它们可用作潜在的可生物降解骨折固定装置，用于骨愈合。