【作者】 查磊；

【导师】 刘寅； 毛用敏； 曹路；

【作者基本信息】 天津医科大学 ， 内科学， 2010， 硕士

【摘要】 目的：观测微弧氧化(MAO)及聚左旋乳酸(PLLA)封孔表面修饰对生物可降解镁合金材料AZ811耐腐蚀性能、细胞毒性、血液相容性及全身毒性的影响。方法：采用微弧氧化(MAO)及聚左旋乳酸(PLLA)封孔方法对AZ811镁合金表面修饰,以D-Hank’s液作为腐蚀介质,扫描电镜(SEM)观察浸泡前后的镁合金表面微观形貌,评价表面修饰镁合金材料的耐腐蚀性能；制备试件浸提液,体外培养原代人脐动脉平滑肌细胞(HUASMC)及脐静脉内皮细胞(HUVEC),用材料浸提液处理人脐动脉平滑肌细胞及脐静脉内皮细胞,MTT比色法检测吸光度值(OD值),并计算细胞相对增殖率(RGR),判断细胞毒性的级别；以316L不锈钢作为阴性对照,测定与材料表面接触2 min后血浆的凝血时间(PT、RT);测定经材料浸提液处理的2%人血悬液的吸光度值(OD值),计算溶血率(hemolytic ratio),评价表面修饰镁合金用材料的抗凝血及抗溶血性能；对微弧氧化AZ811镁合金的分别进行小鼠急性毒性试验、亚急性毒性试验,观察小鼠临床毒性体征、并取血检测血清Mg2+浓度、肝功能及肾功能；同时取肝脏组织标本作病理学检查,评价表面修饰镁合金用材料的全身毒性。结果：在D-Hank’s液中浸泡1周后,AZ811、MAO/AZ811和MAO+PLLA/AZ811材料均有不同程度的降解；浸泡4周后AZ811表面有结构疏松且分布不均匀的沉淀颗粒堆积,表面孔隙结构增多,出现较重的龟裂,形成大的腐蚀孔洞；MAO/AZ811和MAO+PLLA/AZ811材料浸泡前后变化较轻,且沉淀颗粒较AZ811均匀,未出现明显的腐蚀孔洞,但MAO/AZ811表面膜层局部存在较多的微孔和裂纹；溶解后的PLLA具有较好的流动性,可浸入并填满微弧氧化膜层的孔洞,形成有效的封孔,封孔后的表面致密、平滑。各组细胞生长情况良好,经MAO及MAO+PLLA表面修饰的AZ811镁合金对细胞的生长增殖表现出良好的细胞相容性,其细胞相对增殖率较高而细胞毒性较低。随时间的推移,浸提液内细胞生长没有受到明显抑制,细胞毒性评级为1级,且MAO/AZ811组及MAO+PLLA/AZ811组的细胞相对增殖率均高于AZ811组。各组之间PT比较差异无统计学意义(P>0.05)；RT测定结果表明,AZ811组、MAO/AZ811组、MAO+PLLA/AZ811组均高于316L组(均P<0.05), MAO/AZ811组与MAO+PLLA/AZ811组之间差异无统计学意义,溶血试验中,AZ811组、MAO/AZ811组、MAO+PLLA/AZ811组与阴性对照组的OD值比较差异均有统计学意义(P<0.05);MAO/AZ811组、MAO+PLLA/AZ811组的OD值均低于AZ811组(P<0.05);MAO/AZ811组的OD值与MAO+PLLA/AZ811组之间差异无统计学意义；AZ811组、MAO/AZ811组、MAO+PLLA/AZ811组的溶血率(%)分别为2.20、1.19、0.97，均符合生物材料溶血性的要求。急性毒性试验及亚急性毒性试验中,注射浸提液后小鼠未出现临床毒性体征；各组之间肝肾功能比较差异无统计学意义(P>0.05),血清Mg2+浓度没有因为注射镁合金浸提液而升高(P>0.05)；肝脏病理分析显示肝组织结构未受明显影响。结论：镁合金材料AZ811在模拟人工体液中的耐腐蚀性能较差,微弧氧化(MAO)及聚左旋乳酸(PLLA)封孔表面修饰有效地提高镁合金基体在模拟人工体液中的耐腐蚀性能。MAO及MAO+PLLA表面修饰可以降低AZ811镁合金的细胞毒性,而且MAO及MAO+PLLA表面修饰AZ811镁合金是一种细胞相容性较好的合金材料。AZ811、MAO/AZ811和MAO+PLLA/AZ811具有良好的抗凝血性能,同时MAO及MAO+PLLA表面修饰可减缓AZ811快速降解,从而避免血液中碱性环境造成的溶血,MAO及MAO+PLLA表面修饰可进一步改善AZ811镁合金的血液相容性。表面修饰AZ811镁合金材料无明显全身毒性作用。更多还原

【Abstract】 Objeetives:To evaluate the effects of micro-arc oxidation (MAO) and poly-L-lactic acid (PLLA) surface-modification on the corrosion resistance, cytotoxicity, blood compatibility and general toxicity of magnesium alloy AZ811.Methods:Micro-arc oxidation surface-modificated AZ811(MAO/AZ811) materials and MAO+poly-L-lactic acid (PLLA) surface-modificated AZ811 (MAO+PLLA/ AZ811) materials were prepared, the surface topography of materials in the physiological environment in vitro was observed by scanning electron microscopy (SEM). The human Umbilical Artery Smooth muscle cells (HUASMCs) and the human umbilical vein endothelial cells (HUVECs) were treated by leaching liquor of materials, the relative growth rate (RGR) was assessed by MTT assay to evaluate the level of cytotoxicity. Micro-arc oxidation surface-modificated AZ811(MAO/AZ811) materials and MAO+poly-L-lactic acid (PLLA) surface-modificated AZ811 (MAO+PLLA/AZ811) materials were prepared, coagulation time (PT, RT) and hemolytic ratio were determined to evaluate the blood compatibility of those materials. Acute toxicity test and subacute toxicity test were performed on Kunming mice with leaching liquor of MAO/AZ811 and MAO+PLLA/AZ811 materials, then the biochemical indicatorswere and the pathological change of liver were checked after 4 weeks.Results:The observation of scanning electron microscopy indicated that AZ811 corroded seriously after immersion and there was no apparent obvious corrosion holes on the the surface of MAO/AZ811 and MAO+PLLA/AZ811 materials after immersion. HUASMCs and HUVECs showed normal Proliferation and morphology, the cytotoxieity of AZ811 Magnesium alloy made from MAO and MAO+PLLA was 1 grade. It was found that there were good anticoagulant properties but lower hemolysis rate of MAO/AZ811 and MAO+PLLA/AZ811 materials. There was no significant abnormality found in biochemical indicators and pathological analysis in acute toxicity test and subacute toxicity test.Conclusion:MAO and MAO+PLLA surface modification improved the corrosion resistance of AZ811 magnesium alloy. It was found that there were no apparent cytotoxicity of MAO/AZ811 and MAO+PLLA/AZ811 materials. MAO and MAO+PLLA surface modification improved the blood compatibility of AZ811 magnesium alloy. It was found that there were no apparent general toxicity of MAO/AZ811 and MAO+PLLA/AZ811 materials.更多还原