目的：探讨5-氨基乙酰丙酸-光动力疗法(5-aminolevulinicacid-mediatedphotodynamictherapy,ALA-PDT)在小鼠骨髓移植后减轻急性移植物抗宿主病(graft-versus-hostdisease,GVHD)的作用。方法：建立同种异基因小鼠骨髓移植急性GVHD模型,以C57BL/6J为供鼠,BALB/C为受鼠。BALB/C受鼠经致死剂量(8.5Gy)60Co照射后随机分为4组,A组为单纯60Co照射组;B组为单纯供鼠骨髓及脾细胞移植组;C组为供鼠骨髓移植以及供受鼠混合脾细胞移植组;D组为ALA-PDT移植组。在照射后4h移植供鼠骨髓细胞和脾细胞。观察骨髓移植后受鼠的一般情况、28d生存率、外周血白细胞计数以及肝脏、小肠、皮肤的病理组织学改变,应用流式细胞仪检测骨髓移植细胞嵌合情况。结果：D组小鼠28d生存率明显高于其他各组,差异有显著性(P<0.01),28d各组小鼠存活率分别为:0,0,10%,60%。B,C组小鼠均出现GVHD反应,其血液学以及病理组织学改变的严重度与GVHD发生的早晚具有一定的相关性。D组仅有2只小鼠出现GVHD反应,但其血液学以及病理组织学改变程度较其他各组轻。结论：ALA-PDT能够明显减轻小鼠骨髓移植后GVHD反应,增加受鼠的28d生存率,因此可能是一种有价值的抗同种异基因骨髓移植后急性GVHD反应的治疗方法。

OBJECTIVE: This study investigated the hypothesis that 5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) might alleviate acute graft-versus-host disease (GVHD) following allogenic bone marrow transplantation (allo-BMT) in mice. METHODS: Acute GVHD model following allo-BMT was established in 40 recipient BALB/C mice. Fifty C57BL/6J mice were used as donors and another 10 BALB/C mice as blank control without any intervention. Recipients received a lethal dose of 8.5 Gy ~ 60 Co radiation for 10 minutes before transplantation and then were randomly divided into four groups of 10 mice (A-D). Group A was injected with normal saline injection and served as controls. Group B received pure donor bone marrow and spleen cell infusion. Group C received donor bone marrow and mixed donor-recipient spleen cell infusion. Group D was administered with an infusion of donor bone marrow cells and mixed donor-recipient spleen cells treated with ALA-PDT. The 28th day survival rate, incidence of acute GVHD and hematological and pathological changes after transplantation were examined. RESULTS: All the mice from the Blank control group survived. The survival rates for Groups A-D on the 28th day were 0, 0, 10% and 60% respectively. Group D showed a significantly higher survival rate than the other three groups (P<0.01). Most of the mice in Groups B and C developed GVHD but only two developed in Group D. Moreover Group D had less severe hematological and pathological changes when compared with Groups B and C. CONCLUSIONS: ALA-PDT significantly alleviated GVHD and increased the 28th day survival rate for allo-BMT mice. ALA-PDT may be a promising therapy for GVHD following allo-BMT. Future studies should focus on the underlying mechanism of its therapeutic effect.