树突状细胞诱导大鼠肝移植免疫耐受的研究

An experimental study on immune tolerance of rat liver transplantation induced by dendritic cells

目的观察大鼠骨髓来源的树突状细胞（DC）对同种异体肝移植大鼠免疫耐受的影响。方法用不同细胞因子诱导培养大鼠骨髓来源的成熟DC（mDC）和不成熟DC（imDC），采用形态学观察、表型分析和功能学实验对培养细胞进行鉴定，构建Wistar大鼠和SD大鼠肝移植模型，并于移植前5d注射到受体大鼠内，研究它们对移植后大鼠肝脏病理及存活时间的影响情况。结果DC细胞形态不规则，大多数细胞表面有细长树枝状突起，mDC和imDC表面均表达表面分子OX62，而表面分子CD86在imDC表面低表达，在mDC表面高表达。imDC和mDC与淋巴细胞相互作用，发现imDC对淋巴细胞的增殖无明显作用，相反mDC对淋巴细胞的增殖有明显的促进作用。注射imDC的受体大鼠的存活时间显著长于注射mDC的受体大鼠，注射mDC的肝移植大鼠在移植后较早且出现较强的急性排斥反应，而注射mDC的大鼠在移植后16d才开始出现轻度急性排斥反应。结论建立了在体外大量扩增大鼠骨髓来源DC的方法，imDC能显著延长受体大鼠肝移植的存活时间。

Objective To explore the immue tolerance induced by in vivo injection of bone marrow-derived dendritic cells in rats. Methods Immature dendritic cells （imDC） and mature dendritic cells （mDC） derived from rat bone marrow were propagated in vitro under different cytokines. The mDC and imDC harvested were identified with morphology, phenotype and mixed lymphocyte reaction-stimulation activity （MLR）. Orthotopic transplantion in Wistar rats receiving SD rats liver was performed, mDC and imDC were administered to recipients 5 days before transplantation by intraperitoneal injection, and the liver allograft survival and liver pathologic changes were observed. Results The appearance of DC was irregular, and presented various length, mDC and imDC expressed ox-62 surface molecule, mDC showed much higher expression of CD86 than imDC. The strongest proliferation of MLR was induced by imDC ,while the imDC did not stimulate the T cells in MLR. After DC were administered to recipients 5 day before transplantation by intraperitoneal injection, the liver allograft survival time was much longer in the imDC group than in the mDC group and control group. At the same time, the rats in mDC group showed severer and earlier acute rejection after liver transplantation, but in imDC group acute rejection was milder 16 days after transplantation. Conclusion A method to propagate large number of DC from rat bone marrow in vitro was established. The therapy of imDC can induce immue tolerance of liver transplantion.