异种骨软骨移植免疫反应及愈合特点的实验研究

目的了解异种骨软骨移植免疫反应及愈合的特点。方法取成年新西兰白兔36只作为实验动物以及自体骨软骨移植和同种异体骨软骨移植的供体,健康家猪1只作为异种骨软骨移植的供体。将实验动物随机分为A、B、C三组,每组12只,分别为自体组、同种异体组和异种组,在实验动物右股骨滑车部制造骨软骨缺损模型,分别进行柱状自体、同种异体和异种骨软骨移植。分别于术后2周、4周、12周取外周血进行IL-2、IL-4和IFN-γ检测。分别于术后4周及12周随机处死每组中的6只实验动物,取其股骨远端骨软骨、滑膜组织以及关节液标本,进行大体观察、组织学检查和IL-2、IL-4和IFN-γ检测。结果 Moran大体观察评分结果显示,C组在4周时评分低于A组及B组;在术后12周时低于A组,但与B组的评分差异无显著性。血清及关节液中细胞因子检测结果显示,术后2周时,C组血清的IFN-γ浓度低于A组及B组;C组血清的IL-4浓度高于A组及B组。术后4周时,C组关节液中的IFN-γ浓度高于A组;C组关节液中的IL-2浓度高于A组及B组;C组血清的IL-4浓度高于B组,关节液中的IL-4浓度高于A组,但低于B组。术后12周时,C组血清的IFN-γ浓度高于A组及B组,关节液中的IFN-γ浓度高于A组;C组血清的IL-2浓度高于A组及B组,关节液中的IL-2浓度高于A组及B组;C组关节液中的IL-4浓度高于A组。组织学检查结果显示,术后4周时,B组术侧膝关节滑膜组织中有炎细胞浸润,至术后12周时组织学表现基本正常。C组在术后4周时术侧膝关节滑膜组织中有大量炎细胞浸润,12周时炎细胞数量减少,但仍然明显多于B组。同时在A组中也发现个别滑膜标本中存在少量炎细胞浸润。结论异种骨软骨移植的免疫反应特点与同种异体骨软骨移植不同,其早期排斥反应强,后期弱,早期以Th2反应为主,而同种异体骨软骨移植免疫排斥以Th1反应为主。愈合过程则是骨吸收发生较晚,而同种异体移植骨吸收发生较早。

A study on the immune responses and the healing of osteochondral xenograft

Objective To investigage the immune responses and the healing of osteochondral xenograft.Methods 36 New Zealand rabbits were used as transplant recipients and transplant donors for autografts and allografts.1 pig was used as transplant donor for xenografts.Rabbits were randomly divided into three groups: Group A for autografts;Group B for allografts and Group C for xenografts.Osteochondral defection models were made on the femoral trochleae of each rabbits.At the 2,4 and 12 weeks after surgery,peripheral blood samples were collected to detect IL-2,IL-4 and IFN-γ.At the 4 and 12 weeks after surgery,6 rabbits in each groups were killed to obtain distal femur samples,synovial tissue samples and synovial fluid samples for gross observation,pathological testing and detecting IL-2,IL-4 and IFN-γ.Results Moran gross scoring shows that the scores of Group C is lower than Group A and Group B at the 4 weeks after surgery;at the 12 weeks after surgery,the scores of Group C is lower than Group A,but no significant difference with Group B.Results of cytokine in the blood serum and the synovial fluid demonstrated that at 2 weeks after surgery,the IFN-γ level in the blood serum of Group C is lower than Group A and Group B;the IL-4 level in the blood serum of Group C is higher than Group A and Group B.After 4 weeks of the surgery,the IFN-γ level in the blood serum of Group C is higher than Group A;the IL-2 level in the synovial fluid of Group C is higher than Group A and Group B;the IL-4 level of Group C is higher than Group B in the blood serum,in the synovial fluid,the IL-4 level of Group C is higher than Group A,but lower than Group B.After 12 weeks of the surgery,the IFN-γ level in the blood serum of Group C is higher than Group A and Group B,and higher than Group A in the synovial fluid;the IL-2 level in the blood serum is higher than Group A and Group B,as well as in the synovial fluid;the IL-4 level in the synovial fluid of Group C is higher than Group A.The result of the pathological testing shows that the synovial tissues of Group B were infiltrated by inflammatory cells,and were anastatic at the 12 weeks after surgery.Massive inflammatory cells were found in the synovial tissues of Group C,which were reduced at the 12 weeks after surgery,but still more than Group B.Mild inflammatory cells infiltration were found in some synovial samples of Group A.Conclusion The mechanism of the immune responses and the healing of osteochondral xenograft is different from allografts.The immune responses of xenografts are stronger than allografts,especially in the early stage.The rejection of xenografts is mainly associated with Th2-type cell response,whereas the allografts with a Th1-type.The occurrence of the resorption of xenografts are later than allografts.