BACKGROUND Xenogeneic bone has been widely used in a variety of clinical bone-related disease to promote bone healing and restore bone defects. However, the adverse effects of immune system limit its application in the clinic. The aim of this study was to evaluate xenogeneic bone safety of immunotoxicity and explore the methods for immune risk supervision. RESULTS Xenogeneic bone, which is freeze-dried bovine cancellous bone, was implanted into the muscle of mice. On day 7, 14 and 28, the effects of xenogeneic bone were examined on humoral immunity and cellular immunity, including the levels of IgG, IgM, C3, inflammatory factors (TNF-α, IL-6), alkaline phosphatase (ALP) and the lymphocyte phenotype. The data showed that xenogeneic bone implantation had no potential to induce immune responses not only in humoral immunity but also in cellular immunity. To reveal the risk of immunogenicity, the residual DNA and the clearance of α-gal epitope were analyzed in 2 different bones (bone 1 is deproteinized bone, bone 2 is acellular and defatted bone). It was suggested that DNA of xenogeneic bone can be limited to < 50 ng per mg dry weight for the repair or regeneration with the acceptable immune risk. And α-gal clearance of xenogeneic bone could be an effective risk factor for improving xenograft quality management. CONCLUSIONS Through the detection of xenogeneic bone immunotoxicity, our findings indicated that the supervisions of risk factors could contribute to reduce the immune risk. And the risk factors under the acceptable limitation could decrease or replace animal experiment. However, it still needs to be studied on the limitation of α-gal epitope to predict rejection of xenogeneic bone more accurately.

中文翻译：

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异种骨免疫毒性评估和风险管理研究。

背景技术异种骨已被广泛用于多种临床上与骨相关的疾病中，以促进骨愈合和恢复骨缺损。但是，免疫系统的不良影响限制了其在临床中的应用。这项研究的目的是评估免疫毒性的异种骨安全性，并探索免疫风险监督的方法。结果异种骨是冻干的牛松质骨，被植入小鼠的肌肉中。在第7、14和28天，检查异种骨对体液免疫和细胞免疫的影响，包括IgG，IgM，C3，炎性因子（TNF-α，IL-6），碱性磷酸酶（ALP）和淋巴细胞表型。数据表明，异种骨植入不仅在体液免疫方面而且在细胞免疫方面都没有诱导免疫反应的潜力。为了揭示免疫原性的风险，在2条不同的骨头（骨头1是去蛋白的骨头，骨头2是无细胞的骨头和脱脂的骨头）中分析了残留的DNA和α-gal表位的清除率。建议将异种骨的DNA限制为每毫克干重<50 ng，以进行修复或再生，并具有可接受的免疫风险。异种骨的α-gal清除可能是改善异种移植质量管理的有效危险因素。结论通过检测异种骨免疫毒性，我们的发现表明，危险因素的监督可有助于降低免疫风险。在可接受范围内的危险因素可以减少或代替动物实验。然而，仍然需要研究α-gal表位的局限性以更准确地预测异种骨的排斥。