Assad M, Yahia L H, Rivard C H, Lemieux N
Centre de Recherche Pédiatrique, Hôpital Ste-Justine, Montréal, Québec, Canada.
J Biomed Mater Res. 1998 Jul;41(1):154-61. doi: 10.1002/(sici)1097-4636(199807)41:1<154::aid-jbm18>3.0.co;2-n.
Shape memory nickel-titanium (NiTi) alloys are potential candidates for biomedical applications. However, their equiatomic composition (50 wt% Ni) is controversial, and concerns have been raised about their biocompatibility level because of the carcinogenicity potential. The relative in vitro genotoxicity of NiTi therefore was evaluated and compared to commercially pure titanium (cpTi), 316L stainless steel (SS 316L), and positive and negative controls. To do so, human peripheral blood lymphocytes were cultured in semiphysiological medium that previously had been exposed to the biomaterials. The electron microscopy in situ end-labeling (EM-ISEL) assay then was performed in order to provide quantification of in vitro chromatin DNA single-stranded breaks (SSBs). Chromosomes and nuclei were harvested and exposed to exonuclease III, which amplifies DNA lesions at 3' ends of breaks. After random priming, incorporation of biotin-dUTP was labeled by immunogold binding, which then was detected using electron microscopy. Cellular chromatin exposed to the positive control demonstrated a significantly stronger immunogold labeling than when it was exposed to NiTi, cpTi, SS 316L extracts, or the untreated control. Moreover, gold particle counts, whether in the presence of NiTi, cpTi, or the negative control medium, were not statistically different. NiTi genocompatibility therefore presents promising prescreening results towards its biocompatibility approval.
形状记忆镍钛（NiTi）合金是生物医学应用的潜在候选材料。然而，它们的等原子组成（50 wt% Ni）存在争议，并且由于潜在的致癌性，人们对其生物相容性水平表示担忧。因此，对NiTi的相对体外遗传毒性进行了评估，并与商业纯钛（cpTi）、316L不锈钢（SS 316L）以及阳性和阴性对照进行了比较。为此，将人类外周血淋巴细胞在先前已暴露于生物材料的半生理培养基中培养。然后进行电子显微镜原位末端标记（EM-ISEL）测定，以定量体外染色质DNA单链断裂（SSB）。收获染色体和细胞核并将其暴露于核酸外切酶III，该酶可放大断裂3'末端的DNA损伤。随机引物后，通过免疫金结合标记生物素-dUTP的掺入，然后使用电子显微镜进行检测。与暴露于NiTi、cpTi、SS 316L提取物或未处理对照相比，暴露于阳性对照的细胞染色质显示出明显更强的免疫金标记。此外，无论在存在NiTi、cpTi还是阴性对照培养基的情况下，金颗粒计数均无统计学差异。因此，NiTi的遗传相容性在其生物相容性批准方面呈现出有前景的预筛选结果。
