可降解锌合金植入材料的体内抗菌性

Antibacterial properties of biodegradable zinc alloys in vivo

背景:锌是无机抗菌材料,具有适宜的降解速率和良好的抗菌特性,通过添加合金元素可改善材料的力学性能和生物相容性,是目前医用新型可降解金属材料的发展方向,目前尚缺乏不同锌基材料之间抗菌性能比较的研究。目的:比较纯锌及锌基合金材料的体内抗菌性能。方法:取80只SPF级SD大鼠,分别制备金黄色葡萄球菌和大肠杆菌感染动物模型,每种模型40只。将纯锌及锌基合金材料(纯锌、锌铝合金、锌锶合金、锌镁合金、锌银合金、锌钙合金和锌铜合金)分别植入2种模型大鼠股骨骨髓腔内,并设置未植入任何材料的对照组,每组5只。植入后第1,4,7,14天,检测大鼠体温变化、血白细胞计数、血清肿瘤坏死因子α和血清锌元素含量,并收集手术部位分泌物及组织,鉴定细菌种类。结果与结论:①经金黄色葡萄球菌或大肠杆菌感染后,各组大鼠体温均有不同程度升高,纯锌及锌基合金材料植入组第7,14天的体温显著低于对照组(P <0.05),且锌银合金组第7,14天的体温显著低于纯锌及其他锌基合金材料组(P<0.05);②材料植入2种感染模型后第7,14天,对照组白细胞计数和肿瘤坏死因子α浓度显著高于纯锌及锌基合金材料组(P <0.05),且锌银合金组大白细胞计数和肿瘤坏死因子α浓度显著低于纯锌及其他锌基合金材料组(P <0.05);③在2种感染模型中,各组血锌元素含量无差异(P> 0.05);④金黄色葡萄球菌感染组细菌鉴定为金黄色葡萄球菌(+),大肠杆菌感染组细菌鉴定为大肠杆菌(+); ⑤结果提示,可降解锌基合金植入材料在大鼠体内具有良好的抗菌效果,而锌银合金抗菌能力最强。

BACKGROUND: Zinc, an inorganic antibacterial material, has a suitable degradation rate and good antibacterial property. Adding alloying elements can improve the mechanical properties and biocompatibility of the material, which is the development direction of novel medical biodegradable metal materials. There is still lack a comparable research on the antibacterial properties among zinc-based materials. OBJECTIVE: To investigate the antibacterial properties of pure zine and zinc-based alloys in vivo. METHODS: Eighty Sprague-Dawley rats, SPF grade, were randomized into two groups (n=40/group), and all rats were injected with Staphylococcus aureus or Escherichia coli solution to prepare infection models. Different materials (Zn, ZnAl, ZnSr, Zn3Mg, Zn3Ag, Zn3Ca and Zn4Cu;five rats for each material) were implanted into the medullary cavity of femur. The control group without any material was set. At 1, 4, 7 and 14 days after implantation, the changes of body temperature, white blood cell count, serum tumor necrosis factor α and serum zinc content in rats were detected. The secretions and tissues of the surgical site were collected to identify the bacterial species. RESULTS AND CONCLUSION:(1) The body temperature in all the rats was increased to different extents after bacterial infection, but the temperature of the rats implanted with zinc and zinc alloys was always lower than that in the control group at 7 and 14 days (P < 0.05). The temperature in the Zn3Ag group was significantly lower than that in the other groups at 7 and 14 days (P < 0.05).(2) The white blood cell count and tumor necrosis factor α level in the zinc and zinc alloys groups were significantly lower than those in the control group at 7 and 14 days after implantation (P < 0.05). The white blood cell count and tumor necrosis factor α level in the Zn3Ag group were significantly lower than those in the other groups (P < 0.05).(3) The serum zinc content in all groups has no significant difference (P > 0.05).(4) The bacterial culture results showed S.aureus (+) in the Staphylococcus aureus infection group and E.coli (+) in the Escherichia coli infection group.(5) To conclude, degradable zinc-based alloys exert marked antibacterial effects, and Zn3Ag alloys have the best antibacterial activity.