中国组织工程研究

中国组织工程研究 ›› 2016, Vol. 20 ›› Issue (16): 2303-2309.doi: 10.3969/j.issn.2095-4344.2016.16.003

• 组织工程骨及软骨材料 tissue-engineered bone and cartilage materials • 上一篇    下一篇

AZ31镁合金材料植入物在兔股骨髁内的降解：Micro-CT评价

徐亦驰，尹合勇，孙 振，孟昊业，肖 波，汪爱媛，郭全义，彭 江，卢世璧   

  1. 解放军总医院骨科研究所、骨科再生医学北京市重点实验室(编号：BZ0128)、全军骨科战创伤重点实验室，北京市 100853
  • 收稿日期:2016-03-06 出版日期:2016-04-15 发布日期:2016-04-15
  • 通讯作者: 卢世璧，院士，教授，主任医师，博士生导师，解放军总医院骨科研究所、骨科再生医学北京市重点实验室(编号：BZ0128)、全军骨科战创伤重点实验室，北京市 100853
  • 作者简介:徐亦驰，男，1991年生，河南省驻马店市人，汉族，解放军总医院骨科在读硕士。
  • 基金资助:

    国家自然科学基金(NFSC，51361130034)；国家重点基础研究发展计划(973计划，2012CB518106)；军队十二五发展计划(BWS11J025)；北京市自然科学基金(Z141107004414044)

Degradation of AZ31 magnesium alloys in vivo: micro-CT assessment

Xu Yi-chi, Yin He-yong, Sun Zhen, Meng Hao-ye, Xiao Bo, Wang Ai-yuan, Guo Quan-yi, Peng Jiang, Lu Shi-bi   

  1. Institute of Orthopaedics of Chinese PLA General Hospital, Beijing Key Laboratory of Orthopedic Regenerative Medicine (No. BZ0128), Key Laboratory of Musculoskeletal Trauma & War Injuries of PLA, Beijing 100853, China
  • Received:2016-03-06 Online:2016-04-15 Published:2016-04-15
  • Contact: Lu Shi-bi, Academician, Professor, Chief physician, Doctoral supervisor, Institute of Orthopaedics of Chinese PLA General Hospital, Beijing Key Laboratory of Orthopedic Regenerative Medicine (No. BZ0128), Key Laboratory of Musculoskeletal Trauma & War Injuries of PLA, Beijing 100853, China
  • About author:Xu Yi-chi, Studying for master’s degree, Institute of Orthopaedics of Chinese PLA General Hospital, Beijing Key Laboratory of Orthopedic Regenerative Medicine (No. BZ0128), Key Laboratory of Musculoskeletal Trauma & War Injuries of PLA, Beijing 100853, China
  • Supported by:

    the National Natural Science Foundation of China, No. 51361130034; the National Key Basic Research Development Program of China (973 Program), No. 2012CB518106; Twelfth Five-Year Development Plan of PLA, No. BWS11J025; the Natural Science Foundation of Beijing, No. Z141107004414044

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摘要：

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文题释义：
Micro-CT：又称微型CT、显微CT、微计算机断层扫描技术，是一种非破坏性的3D成像技术，可以在不破坏样本的情况下清楚了解样本的内部显微结构。它与普通临床的CT最大的差异在于分辨率极高，可以达到微米级别，因此具有良好的“显微”作用。
镁合金：镁金属及其合金因其具有相当多的优势在近年来广泛被临床各科研究，但迄今为止仍未在骨科临床中广泛应用，主要原因是材料其在体内降解的不稳定性，过快的降解导致骨折愈合前已丧失机械完整性，而且还存在着材料降解过程中产生氢气的安全隐患。
 
背景：因为镁在体内可自行降解，避免二次手术，但镁合金材料还未能在骨科临床中广泛应用，且评价其在体内降解的方法仍缺乏高精准性和可靠性。
目的：通过Micro-CT图像和相关数据评价AZ31镁合金在兔股骨髁内的降解。
方法：将40个表面微弧氧化处理的AZ31镁合金棒材植入至40只新西兰大白兔的右侧股骨髁。植入后5，10，15，20周每个时间点依次取出10只兔的右侧股骨髁，利用Micro-CT扫描图像以及生成数据定量地对镁合金的降解进行分析和评价。
结果与结论：①镁合金材料降解过程中的一般形态：植入后第5-20周，镁棒表面被腐蚀程度逐渐加重，色泽变灰暗，形状出现变形；②Micro-CT图像检测：植入前5周内镁合金降解程度十分微小，只有少量腐蚀点，植入后第10周时侵蚀点有所增加，而到植入后第15周时，镁棒表面腐蚀点明显增多，腐蚀面积更大，且与植入前10周相比加速更明显，到植入后第20周时镁棒表面几乎布满了腐蚀点，且表面粗糙、不连续。③数据分析：植入前5周，镁棒的体积分数保持在98.6%，降解缓慢，植入后第10周时降至97.1%，但仍较为缓慢，植入后第10-15周此指标出现了明显的降低(P < 0.05)，到第20周时已降至了86.4%(P < 0.05)，而在植入15-20周中，镁棒体积分数减少了6.5%，达到单位周期的体积减少最大量；随着腐蚀的进展，镁棒表面变得粗糙、模糊，表面积变大，镁棒表面积与体积之比持续增加，且至第15，20周的增加量差异有显著性意义(P < 0.05)；镁棒表面生成的腐蚀点越来越多，导致横截面半径减小，反映在数据中即“骨小梁厚度”的降低，该数值从1.00 mm降至第20周的0.87 mm， 从曲线斜率来看，第10-15周该数值降低速度最快；整个实验中镁矿物密度持续降低，且在第10-15周降低速度最快，到20周时，已由开始时的649.302 mg/cm3降至356.445 mg/cm3 (P < 0.05)；另一方面，镁合金Micro-CT图像密度从实验开始时的679.710 mg/cm3最后降至 644.947 mg/cm3，但差异无显著性意义。④结果证实：植入后10-20周是镁合金降解速度的高峰期，伴随镁合金的降解，其含量降低，但密度并不因其材料降解而降低。
中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程
ORCID: 0000-0002-0916-834X(卢世璧)

关键词: 生物材料, 骨生物材料, 镁合金, 微弧氧化, Micro-CT, 股骨髁, 大体观, 降解, 体内实验, 国家自然科学基金

Abstract:

BACKGROUND: Magnesium can be degraded voluntarily in vivo, so a second surgery is avoided. However, its alloys have not been widely used in the clinical orthopedics because there is a lack of accurate and reliable methods to assess its degradation in vivo.
OBJECTIVE: To explore the degradation of micro-arc-oxidized AZ31 magnesium alloy in the femoral condyle of rabbits based on micro-CT images and relative data.
METHODS: Forty micro-arc-oxidized AZ31 magnesium alloys were implanted into the right femoral condyle of 40 New Zealand rabbits. Then 10 right femoral condyles were removed at 5, 10, 15 and 20 weeks after surgery, respectively, to quantitatively analyze and evaluate the degradation of AZ31 magnesium alloys by micro-CT images and relative data.
RESULTS AND CONCLUSION: The surface of AZ31 alloys was corroded progressively with dark color and distorted appearance at 5-20 weeks post implantation. Micro-CT images showed that in the first 5 weeks, the degradation was inactive, and at the 10th week, it turned active; at the 15th week, the corrosion pits were obviously increased in number, and the corrosion area and corrosion speed were enlarged and fastened, respectively. Up to the 20th week, the alloy surfaces were full of corrosion pits besides roughness and discontinuity. Relevant data analysis showed that the volume fraction of magnesium alloy was 98.6%, 97.1% and 86.4% at the 5th, 10th and 20th weeks after implantation, respectively, and it had a significant decrease from the 10th to 15th week and from the 15th to 20th week (P < 0.05). Within 15-20 weeks, the volume fraction of magnesium alloy was decreased by 6.5% that was the maximum volume reduction per unit cycle. With the progress of corrosion, the surface continuously became rough and vague, and its surface area was enlarged; the ratio of surface area to volume continuously increased, and there was a significant difference at 15 and 20 weeks (P < 0.05). Because of the increasing number of corrosion pits, the cross-sectional radius decreased, which was reflected by the trabecular thickness decreasing from 1.00 to 0.87 mm. From the view of the slope of curve, the trabecular thickness decreased most rapidly at 10-15 weeks. The mineral density of magnesium alloy continuously decreased from 649.302 to 356.445 mg/cm3 during the whole experiment period (P < 0.05). In addition, the micro-CT image density decreased from 679.710 to 644.947 mg/cm3, but there was no significant difference. To conclude, the degradation speed is peaked at 10-20 weeks after implantation, and the content of magnesium alloys decrease with degradation, but the magnesium density has no significant change.
中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程

Key words: Tomography, Spiral Computed, Magnesium, Absorbable Implants, Femur, Biodegradation, Environmental, Tissue Engineering