部分股骨移植:一个新的带血管的骨髓移植模型

Partial Femur Transplant: A New Model of Vascularized Bone Marrow Transplantation

目的:大鼠后肢移植是带血管的骨髓移植的主要模型,同时含有骨髓和骨髓微环境,有利于免疫耐受的诱导。但其成分复杂,为研究其中骨髓的作用,构建一个成分相对单一的带血管的骨髓移植模型。方法:以MHC不相符的近交系Lewis和BN大鼠分别作为供体或受体,将含血管蒂的供体2/3股骨移植到受体腹股沟区,显微吻合供受体间的股动静脉。实验分为3组:同基因移植组Lewis→Lewis;排斥组Lewis→BN;免疫抑制组Lewis→BN,术后给予环孢素A。通过大体和病理学检查观察各组移植物存活情况,外周血流式监测排斥组和免疫抑制组的嵌合水平。结果:术后7 d,排斥组排斥反应显著,骨髓细胞明显减少、坏死,外周血嵌合水平几乎为0,而同基因移植组股骨存活良好,骨髓HE染色大致正常,可见髓腔内有大量的嗜碱性骨髓细胞;术后60 d,同系移植组和免疫抑制组的大体观察及组织病理学大致相同,均证实移植物存活良好,同时流式可见免疫抑制组术后7、28、60 d外周血中存在供体特异性的嵌合。结论:带血管蒂的部分股骨移植物是一个简便可靠的带血管的骨髓移植模型,嵌合分析表明其具有诱导耐受的潜能,有利于阐明异体复合组织中骨髓对免疫耐受诱导的作用和机制。

Objective： Hind limb transplant is the most commonly model for vascularized bone marrow transplantation（VBMT） study in rats because bone morrow and its microenvironments are transplanted as well,thus creating immediate bone marrow space and engraftment.However,it also contains a skin component and other musculoskeletal tissues that complicate issues related to tolerance induction.Then an isolated vascularized bone marrow transplant model was created to study the single aspect of bone marrow in composite allografts.Methods： Fully MHC mismatched BN and Lewis rats were used as donors and recipients respectively,the 2/3 femur from donor was transplanted into the recipients inguinal region,and their nutrient vessels were anastomosed with recipients vessels.3 experimental groups were carried out.The syngeneic group,isograft transplantations were performed between identical Lewis rats.The rejection and immunosuppression groups,allografts were transplanted across major histocompatibility complex barriers between Brown Norway rats and Lewis rats.No treatment was performed rats in rejection group,whereas rats of immunosuppression group received cyclosporine A after allotransplantation.Gross examination and bone specimens were evaluated for the viability of partial femur components,and the chimerism was assessed by flow cytometry among the rejection and immunosuppression groups.Results： Allografts in rejection group showed clear rejection at 7 days after transplantation,and numerous bone marrow cells degenerated or necrosed with almost no chimerism.But the bone grafts of syngeneic group remained viable and the bone marrow maintained normal morphological appearance,showing numerous basophil bone marrow cells within bone marrow.On post operation days 60,histologic results of immunosuppression group was similar with syngeneic groups in gross and histological observation.In addition,donor-specific chimerism was confirmed in peripheral blood at 7,28,60 days post-transplant.Conclusion： Vascularized partial femur grafting is a simple and reliable method for vascularized bone marrow transplantation,and may facilitate inducing chimerism for studying the role of bone marrow in composite allografts.