小鼠50%体积肝脏原位移植实验模型的建立

目的 介绍一种小鼠50%体积的原位肝脏移植实验模型.方法 选择同系雄性C57BL/6小鼠,供、受体各28只.实验分为50%体积移植组和全肝移植对照组.50%肝脏移植物通过切除左侧肝叶获得.供肝经门静脉灌注4℃威斯康星大学保存液.血管重建时,肝上腔静脉端端吻合,门静脉和肝下腔静脉采用袖套法吻合.不作动脉重建.术后观察移植物的存活时间.组织病理学检查肝脏移植物的组织结构和细胞形态,免疫组化检测肝细胞复制情况.结果 小鼠肝脏移植手术成功率为100%.50%体积的小鼠肝脏移植受体存活率为90%(＞15 d).全肝移植受体存活率为100%(＞15 d).所有受体手术无肝期保持在23 min内.术后组织学检查移植肝组织结构良好,全肝移植后肝脏再生反应不明显.50%体积的肝脏移植后激发明显的再生反应.结论 小鼠50%体积的肝脏移植实验模型存活率高,术后激发明显的再生反应.该模型可应用于缺血再灌注损伤和肝脏再生等基础研究.     

大鼠小体积肝脏移植后早期肝内细胞因子的变化

目的 研究不同冷缺血条件下大鼠小体积肝移植(30%标准体积)后早期肿瘤坏死因子α(TNF-α)及白细胞介素6(IL-6)的变化,及其与肝脏再生的关系.方法 建立Lewis大鼠30%标准体积的原位肝移植模型.根据供肝在UW液中冷保存时间的不同,将受者分为3组:冷缺血1 h组、冷缺血8 h组和冷缺血16 h组,每组均为20只.观察受者存活情况至术后第7天,并分别在移植肝恢复血流后90 min、1 h、2 h、4 h和7 d收集样本,检测移植肝组织中TNF-α和IL-6表达情况,肝细胞DNA的合成情况,进行移植肝的形态学观察.结果 大鼠肝移植手术成功率均为100%.移植后第7天,冷缺血1 h和8 h组受鼠的存活率均为100%.冷缺血16 h组受鼠的存活率较低,移植后第7天无受鼠存活.冷缺血1 h组TNF-α和IL-6的表达水平较低,冷缺血8 h组和冷缺血16 h组TNF-α和IL-6的表达则高于冷缺血1 h组(F=58.81和F=184.12,P<0.05).冷缺血8 h组和冷缺血16 h组间TNF-α和IL-6的表达的差异无统计学意义.冷缺血1 h组增殖细胞数目明显高于冷缺血8 h组,差异有统计学意义(t=5.59,P<0.05).移植术后24h,冷缺血1 h组移植肝有轻度的组织学损伤;冷缺血8 h组移植肝有轻度的窦状隙扩张和轻度的炎症;冷缺血16 h组移植肝有局部淤血,存在肝细胞崩解和坏死等改变.结论 在小体积肝移植后早期,TNF-α和IL-6的上调表达对肝脏再生有重要意义.不同冷缺血时间的小体积肝脏移植物内存在早期启动肝脏再生的信号.     

保存不同时间的大鼠部分肝脏移植后的肝细胞再生

目的 探讨保存不同时间的大鼠部分肝脏移植后的肝细胞再生及其可能机制.方法 采用近交系雄性Lewis大鼠为供、受者,按照实验设计分别将供肝于4℃UW液中保存1 h(冷缺血1 h组)、8 h(冷缺血8 h组)和16 h(冷缺血16 h组).然后进行原位肝移植.移植肝恢复血流前,用3-0丝线结扎供肝左侧中央叶、左外叶及尾状叶,保留右侧的肝叶.即可制成大鼠50%体积肝脏(以下简称"半肝")原位移植模型.术后观察各组移植肝的存活情况和肝细胞再生情况;采用逆转录聚合酶链反应测定肝组织中自细胞介素-6(IL-6)和肿瘤坏死因子α(TNF_n)的表达情况;采用Western印迹法检测肝组织中信号传导与转录因子-3(STAT-3)表达情况;采用免疫组织化学染色检测移植肝组织中细胞周期素DI(Cyelin D1)的表达和肝细胞摄取溴脱氧尿核苷(BrdU)情况.结果 各组手术成功率均为100%.与冷缺血1 h组相比,冷缺血8 h组和冷缺血16 h组移植肝组织中TNF-a(F=67.45,P<0.05)和IL-6(F=287.73,P<0.05)的表达明显增加.STAT-3的表达也明显增强.肝移植后24 h.冷缺血8 h组在胞浆和细胞核内均有Cyclin D1的表达.而冷缺血16 h组移植肝组织中未见明显的Cyclin D1表达.移植后24 h.冷缺血16 h组的BrdU染色阳性的肝细胞数无明显增多,而在冷缺血8 h组可见BrdU染色阳性的肝细胞明显增多(t=19.40,P<0.05).结论冷保存一定时限的大鼠部分肝脏在移植后可获得肝细胞再生,此过程可能通过TNF-α/IL,16/sTAT-3/Cyclin D1/DNA合成的途径进行调节;当冷保存时间达16 h后,肝细胞不能对肝脏再生早期信号起反应.     

改良的小鼠原位肝移植实验模型

目的 介绍一种稳定、可靠、存活率高的小鼠原位肝移植实验模型。方法 选择同系雄性C57BIV6小鼠，供、受体各22只（其中16只作长期存活观察）。供肝经肝门静脉灌注4℃威斯康星大学保存液。血管重建时，肝上腔静脉端端吻合，肝门静脉和肝下腔静脉采用袖套法吻合。不作动脉重建。术后观察肝移植物组织学改变和肝脏再生反应。结果 小鼠肝脏移植手术成功率为100％。受体存活率为100％（超过30d）。无肝期保持在23min内。术后组织学检查移植肝组织结构良好，肝脏再生反应不明显。结论 改良方法建立的小鼠肝移植实验模型稳定性强，存活率高，精细的显微外科技术是成功的关键。     

受体血清“封闭”供肝预防异种肝移植超急性排斥反应

目的 探讨受体血清“封闭”供肝对异种肝移植超急性排斥反应(hyperacute rejection,HAR)的预防作用.方法 取豚鼠和SD大鼠各20只,分别作为供体和受体,供受体随机配对;移植前采集受体大鼠近交系其他个体血清,45℃水浴灭活补体备用;实验组(n=10)术前用0.1％受体血清(recipient serum,RS)的Ringer液“封闭”供肝,对照组(n=10)仅用Ringer液灌洗供肝;采用改良“双套管法”行豚鼠、SD大鼠原位肝移植,观察供肝植入后形态学改变、受体存活时间、术后1h存活率,HE染色法检测移植肝微血栓、出血和肝细胞水肿等病理损害积分;检测血清丙氨酸转氨酶(ALT)评价肝功能.结果 两组大鼠供体异种肝移植时间和无肝期比较,差异无统计学意义(P＞0.05);对照组受体大鼠供肝充盈缓慢,灌注不均,实验组供肝充盈迅速,灌注较均匀;实验组受体大鼠术后存活时间和术后1h存活率较对照组均明显增加(P＜0.01),移植肝微血栓、间质出血(积分)较对照组明显减轻(P＜0.01),肝细胞水肿无明显差异(P＞0.05);血清丙氨酸转氨酶(ALT)较对照组明显下降(P＜0.05).结论 受体血清“封闭”供肝对异种肝移植HAR具有一定的抑制作用,是预防器官移植HAR的潜在方法之一.     

20%小体积的大鼠肝脏移植模型

目的 应用显微外科技术建立20%小体积移植物的大鼠原位肝脏移植模型.方法 原位移植建立20%小体积大鼠肝脏移植模型.雄性Lewis大鼠40只,供体20只,受体20只.供肝经门静脉用4℃ UW液灌注.肝上下腔静脉用端端吻合连续缝合的方法.肝下下腔静脉和门静脉分别用套管方法固定.套叠缝合法重建肝动脉.胆管重建采用内支架管端端连接的方法.观察移植物的存活率.免疫组化检测肝细胞摄取溴脱氧尿核苷的情况.结果 共施行肝脏移植手术20例,移植手术成功率为100%.20%小体积肝脏移植物的存活率为93.8%(＞14 d).组织学检查移植后的肝脏组织结构良好.移植术后72 h溴脱氧尿核苷染色阳性的肝细胞计数明显增多.结论 20%小体积大鼠肝脏移植物可启动完成移植后的肝脏再生.显微外科技术是移植模型成功的关键.该模型稳定性强,适合于部分肝脏移植领域的基础研究.     

异种肝细胞移植治疗大鼠药物性肝衰的疗效观察

目的　观察异种肝细胞移植治疗大鼠药物性肝衰的疗效。方法　杂种豚鼠为供体 ,胶原酶消化法制备肝细胞。SD大鼠为受体 ,氨基半乳糖 (D GI)腹腔内 1次注射制作肝衰模型。 4 8h后将豚鼠肝细胞(1.5× 10 7个 )移植于大鼠脾内。同种移植及生理盐水为对照。移植后观察受体 2周存活率 ,在移植不同时间作移植物病理及组织化学检查。结果　受体 2周存活率 :异种移植组为 71% ,同种组为69 % (P >0 .0 5 ) ,生理盐水对照组为 2 5 % (P>0 .0 1)。豚鼠肝细胞移植后 12～ 2 4h其结构和功能基本保存完好。结论　与同种移植一样 ,异种肝细胞移植能逆转大鼠药物性肝衰。     

Celsior液与UW液对无心跳大鼠供肝保存效果的比较

目的 比较Celsior(CS)液与UW液对大鼠无心跳供者(NHBD)供肝的保存效果.方法 选取健康雄性SD大鼠作为肝移植的供、受者.通过阻断大鼠主动脉和膈上下腔静脉10 min的方法,制备和获取NHBD供肝,并采用不同的器官保存液灌注和冷保存供肝.随机将受者分为4组.CS8 h组:受者采用经CS液灌注和冷保存8 h的供肝移植;UW8 h组:受者采用经UW液灌注和冷保存8 h的供肝移植;CS16 h组:受者采用经CS液灌注和冷保存16 h的供肝移植;UW16 h组:受者采用经UW液灌注和冷保存16 h的供肝移植.受者门静脉开放前、开放后1、3及6 h,取各组受者的静脉血检测血清丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)、内皮素1(ET-1)、白细胞介素1(IL-1)及肿瘤坏死因子α(TNF-α)水平;观察和比较各组受者的胆汁生成量、移植肝组织病理学改变及术后7 d内的存活率.结果 NHBD供肝经UW液灌注后呈"花斑"状,肝叶边缘灌注不良,经CS液灌注后肝叶边缘灌注良好.CS8 h组和UW8 h组受者的胆汁生成量分别为(0.21±0.01)ml和(0.10±0.02)ml(P<0.05).门静脉开放后1、3及6 h,CS8 h组受者的血清ALT及AST水平明显低于UW8 h组(P<0.05),门静脉开放后1、3h,CS8 h组受者的血清ET-1、IL-1及TNF-α水平均明显低于UW8 h组(P<0.05);CS8 h组受者移植肝肝窦扩张、门静脉充血及炎症细胞浸润等病理学改变明显轻于UW8 h组,CS8 h组和UW8 h组受者术后7 d的存活率分别为58.3%和25.0%(P<0.05).CS16 h组和UW16 h组受者各时点的胆汁分泌量、血清ALT、AST、ET-1、IL-1及TNF-α水平的比较,差异均无统计学意义(P>0.05),两组受者均在术后3 d内死亡,两组受者移植肝组织病理学改变无明显差异.结论 CS液对大鼠NHBD供肝的保存效果优于UW液,这可能与UW液较CS液粘稠及CS液能够减少枯否细胞的激活有关;NHBD供肝的冷保存时间不宜超过16 h.     

外源性IL-6促进IL-6基因敲除小鼠移植肝再生的研究

目的 观察外源性重组白细胞介素6(rIL-6)对白细胞介素6(IL-6)基因敲除小鼠原位肝移植后存活时间和移植肝再生过程的影响.方法 动物为C57BL/6野生型小鼠和IL-6基因敲除小鼠,分为4组进行实验:基因敲除对照组,肝移植供、受者均为IL-6基因敲除小鼠；野生型对照组,以IL-6基因敲除小鼠为供者,野生型C57BL/6小鼠为受者；基因敲除rIL-6组,供、受者均为IL-6基因敲除小鼠,肝移植前1h于受者皮下注射rIL-6,1 mg/kg;野生型rIL-6组,以IL-6基因敲除小鼠为供者,野生型C57BL/6小鼠为受者,受者应用rIL-6,用法和用量同前组.观察受鼠的存活情况.获取移植肝,进行组织学和免疫组织化学检查.结果 供肝冷缺血时间约为50 min.基因敲除对照组受鼠平均存活2.2d,野生型对照组受鼠平均存活1.9 d,基因敲除rIL-6组受鼠平均存活＞17.6 d,野生型rIL-6组受鼠平均存活＞20.4 d.各组间存活时间的差异均有统计学意义(P＜0.01).基因敲除对照组和野生型对照组受鼠移植肝有片状坏死和肝细胞气球样变,有极少数溴脱氧尿核苷染色阳性的细胞存在.基因敲除rIL-6组和野生型rIL-6组受鼠的移植肝无细胞坏死等改变,有散在的肝细胞溴脱氧尿核苷染色阳性.结论 外源性的IL-6能够延长IL-6基因敲除小鼠肝移植后的存活时间,促进其移植肝细胞再生.     

SX-1液对肝脏保存效果的形态学观察

目的 探讨新研制的肝脏灌注保存液SX-1液对保存肝脏的形态学影响.方法 使用SX-1液、威斯康星大学保存液(UW液)和高渗枸橼酸盐腺嘌呤液(HC-A液)保存大鼠肝脏2 h、8 h、24 h后行大鼠原位肝移植(OLT),于移植后6 h处死大鼠提取肝脏组织在光镜进行形态学观察,比较各组保存液对肝脏的保存效果.另外,取SX-...     

ET-Kyoto solution plus dibutyryl cyclic adenosine monophosphate is superior to University of Wisconsin solution in rat liver preservation

ET-Kyoto solution (ET-K) is an extracellular-type organ preservation solution containing the cytoprotective disaccharide, trehalose. A previous study reported the supplement of dibutyryl cyclic adenosine monophosphate (db-cAMP) in conventional ET-K to attenuate lung ischemia-reperfusion injury. In this study, the efficacy of this modified ET-K for liver preservation was investigated by comparison with University of Wisconsin solution (UW). ET-K was supplemented with db-cAMP (2 mmol/L). Lewis rats were randomly assigned to two groups, and liver grafts were flushed and stored at 40C for 24 h with ET-K or UW before syngeneic liver transplantation. The graft function and histological changes at 4 h posttransplant as well as 7-day survival were evaluated. Recipient rat survival rate was significantly higher in the ET-K group than in the UW group. Preservation in ET-K resulted in a significant reduction in serum parenchymal transaminase level and promotion of bile production in comparison with UW. The serum hyaluronic acid level, an indicator of sinusoidal endothelial cell injury, was significantly lower after ET-K preservation than that in UW. Histologically, at 4 h after transplantation, the liver grafts preserved in UW solution demonstrated a greater degree of injury than those in ET-K, which appeared to be apoptosis, rather than necrosis. The continuity of the sinusoidal lining was better preserved in ET-K than in UW. In conclusion, ET-K supplemented with db-cAMP is superior to UW in rat liver preservation. This modified ET-K might therefore be a novel candidate for the procurement and preservation of multiple organs.     

Fate of hepatocyte and sinusoidal lining cell function and kinetics after extended cold preservation and transplantation of the rat liver

We investigated the chronological profile of graft damage and recovery after liver cold ischemia-reperfusion (I/R) injury, with particular attention to the role of apoptosis on hepatocyte and sinusoidal endothelial cell (SEC) damage. Male Lewis rats underwent rearterialized orthotopic liver transplantation using grafts subjected to a short (University of Wisconsin [UW] solution for 1 hour [UW1h]) and prolonged period (UW16h) of cold preservation. Experiments were performed immediately after preservation and 4 hours, 24 hours, 3 days, and 7 days after reperfusion. At each time, graft function, incidence of apoptotic cells, expression of the epitope recognized by a monoclonal antibody specific to rat SECs (SE-1), and incidence of proliferating cells were estimated. In the UW16h group, the proportion of apoptotic SECs was markedly elevated at 4 hours. The incidence of hepatocyte apoptosis was very low, although massive hepatocyte necrosis was evident at 24 hours. The incidence of proliferating hepatocytes and SECs peaked at 3 days, then returned to normal by 7 days. SE-1 expression was reduced immediately after preservation, followed by a marked reduction at 4 and 24 hours after reperfusion, and expression returned to normal by 7 days. Although SEC apoptosis was induced in the early phase of cold I/R injury, hepatocyte damage developed without the occurrence of apoptosis. Regeneration of both hepatocytes and SECs after cold I/R injury peaked at 3 days and was complete by 7 days, whereas functional recovery of these cell populations was complete 3 days after reperfusion. (Liver Transpl 2002;8:370-381.)     

肝移植术中应用S-腺苷-L-蛋氨酸对供肝热缺血损伤的影响

目的探讨术中S-腺苷-L-蛋氨酸（SAMe）加入UW液和血浆冲洗液对热缺血损伤供肝及其恢复的影响。方法建立10min热缺血大鼠肝移植模型，分为A组：UW液灌注＋乳酸钠林格氏液冲洗、B组：UW液灌注＋血浆冲洗、C组：SAMe加入UW液灌注＋血浆冲洗和D组：UW液灌注＋SAMe加入血浆冲洗4组，观察肝组织组织病理学变化和电子显微镜下超微结构变化，并检测血清AST和透明质酸。结果C组和D组术后24h血清AST均低于B组（P〈0．05）。A组术后3h和24h血清HA高于B组（P〈0．05），B组复流后3h及24h血清HA均高于C组和D组（P〈0．05）。组织病理学表现B组复流后3h和24h肝细胞损伤和微循环紊乱较C组和D组明显；超微结构表现，A组复流后3h线粒体肿胀，肝窦内皮细胞肿胀，细胞核不规则，可见内皮细胞凋亡，大部分区域肝窦状隙明显狭窄，内皮层结构模糊，红细胞淤积，受压变形，白细胞附壁，可见内皮层完整性破坏；复流后24h，可见线粒体嵴断裂，核融解。B组内皮细胞损伤较A组轻，C组和D组超微结构表现微循环紊乱和肝细胞损伤表现较B组轻。结论供肝切取术中UW液中加入SAMe灌注保存，血浆冲洗液中加入SAMe可改善热缺血供肝微循环，减轻缺血再灌注损伤，并减轻肝细胞热缺血损伤，有利于10min热缺血供肝功能的恢复。     

SOCS3基因转染对小鼠同种异体移植心脏存活时间的影响

目的研究腺病毒载体介导的细胞因子信号抑制因子3(suppressors of cytokine sig-naling3,SOCS3)基因转染对小鼠同种异体移植心脏存活时间的影响。方法以Balb/c小鼠为供体,以C57BL/6小鼠为受体,行同种异体心脏移植。C57BL/6同种异体小鼠心脏移植受体分为3组(21只/组):(1)对照组,单纯同种异体心脏移植;(2)Ad-SOCS3组,供体术前24h转染2×109pfu编码SOCS3基因的腺病毒载体;(3)Ad-GFP组,供体术前24h转染2×109pfu空病毒载体。每组10只受体用于观察生存期;每组5只受体分别于术后第1、3、5、7、9日处死,获取移植物,采用实时定量逆转录酶聚合酶链反应检测SOCS3mRNA表达的变化;每组6只受体于术后第6日处死,获取移植物和脾脏用于组织学检查及Foxp3mRNA、白介素(IL)-17mRNA表达的检测,同时检测脾脏的混合淋巴细胞反应(mixedlymphocytereaction,MLR)强度,采用流式细胞仪分析调节性T细胞(Treg)及Th17细胞的比例。结果供体术前SOCS3基因转染可明显增加术后移植物内SOCS3 mRNA表达;Ad-SOCS3组的移植心脏存活时间明显长于对照组、Ad-GFP组(P0.05)。术后第6日,Ad-SOCS3组移植物淋巴细胞浸润程度较轻、排斥反应强度级别较低、MLR较弱;该组移植物内Foxp3 mRNA水平及脾脏内CD4+CD25+Treg比例与其他两组比较差异无统计学意义(P0.05),但IL-17 mRNA水平及脾脏内CD4+IL-17+Th17比例较其他两组明显降低(均为P0.05)。结论腺病毒载体介导的供体SOCS3基因转染能够延长移植心脏存活时间,其机制可能与抑制淋巴细胞浸润、抑制T淋巴细胞同种抗原反应性以及抑制Th17免疫反应等有关,与Treg的产生及功能无关。     

Reperfusion rather than storage injury predominates following long-term (48 h) cold storage of grafts in UW solution: studies with Carolina Rinse in rat liver

Both storage injury and reperfusion injury have been reported in association with liver transplantation; however, which predominates is not clear. Therefore, these studies were designed to evaluate whether Carolina Rinse, which minimizes reperfusion injury following orthotopic liver transplantation in the rat, would be effective after long-term (48 h) storage of grafts in University of Wisconsin (UW) cold storage solution where sufficient time for development of storage injury exists. Livers were rinsed with either Ringer's solution or Carolina Rinse solution immediately prior to completion of implantation surgery. In the Ringer's group, 30-day survival was high following 24 h of cold storage (4/5) but was very low after 48 h (1/16). Importantly, survival was increased significantly (5/14) when grafts were rinsed with carolina Rinse following 48 h of cold storage. In both groups, parenchymal cells appeared normal by scanning electron microscopy, excluded trypan blue, and released SGOT at values only slightly above the normal range immediately (i. e., less than 5 min) after 48 h of cold storage. However, SGOT values rose steadily during the 1st hour postoperatively following reperfusion in the Ringer's rinse group and reached levels around 1,000 U/1. In addition, non-parenchymal cells were not labelled with trypan blue following storage, but significant labelling occurred within 1 h. Both SGOT release and nonparenchymal cell injury were reduced significantly when grafts were rinsed with Carolina Rinse prior to completion of surgery. Liver injury assessed histologically 24 h postoperatively was also reduced about 50% by Carolina Rinse. Oxidative stress appeared to be involved, since radical adducts, most likely of lipid origin, were trapped during the first 5 min after reperfusion with the spin trapping technique and detected by electron paramagnetic resonance spectroscopy. Lipid radical formation was reduced nearly completely on reperfusion by Carolina Rinse. Since Carolina Rinse improved survival of liver grafts following long periods of cold storage and reduced lipid radical formation and hepatocellular injury, we concluded that a reperfusion injury rather than a storage injury predominates following orthotopic transplantation of livers stored for long periods of time in cold UW solution.     

Advantages of Celsior solution in graft preservation from non-heart-beating donors in a canine liver transplantation model.

BACKGROUND: The optimal method for preserving livers from non-heart-beating donors (NHBD) is still unknown. We compared the Celsior solution, a new extracellular-type, low-potassium, low-viscosity preservation solution, with the University of Wisconsin (UW) solution in a canine orthotopic liver transplantation from NHBD. MATERIALS AND METHODS: Fourteen adult mongrel dogs, weighing 9 to 17 kg, were divided into two groups: the Celsior or the UW group (n = 7 each). The thoracic descending aorta and supradiaphragmatic inferior vena cava were cross-clamped for 20 min to induce warm ischemia as a NHBD model. The liver was flushed with the respective cold preservation solution and then stored at 4 degrees C for 4 h. The grafts were transplanted using the piggy-back technique under portal decompression by leaving the native right lobe as a temporary shunt. RESULTS: The duration of liver flushing out (min) was shorter (P < 0.05), and the serum glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, lactate dehydrogenase, lactate, and alpha-glutathione S-transferase concentrations 2 and 6 h after reperfusion of the graft (RPF) were lower (P < 0.05) in the Celsior group than in the UW group. Hepatic tissue blood flow (HTBF) did not deteriorate as much (P < 0.05) in the Celsior group. The serum endothelin-1 level was lower (P < 0.05) in the Celsior group 2 h after RPF. Histopathology of liver specimens revealed portal congestion and hepatocyte necrosis with neutrophil infiltration in the UW group, while these findings were mild in the Celsior group. CONCLUSIONS: The Celsior solution improves vascular endothelial injury in livers from NHBDs and may have advantages in graft flush and preservation of grafts from NHBDs.     

供体特异性输注细胞上CD47的表达在小鼠心脏移植免疫耐受中的作用

目的探讨供体特异性输注(donor specific transfusion,DST)细胞上CD47的表达在诱导同种异体小鼠心脏移植免疫耐受中的作用机制。方法实验动物随机分为3组,3组均以C57BL/6(CD47+/+)小鼠为供者,具体分为:(1)non-DST组:以未行CD47+/+DST及CD47-/-DST的BALB/c小鼠为受者。(2)CD47-/-组:以输注CD47-/-DST的BALB/c小鼠为受者。(3)CD47+/+组:以输注CD47+/+DST的BALB/c小鼠为受者。于术前7d、5d、3d分别接受共刺激因子封闭。观察心脏移植物存活时间;用流式细胞技术检测受体脾脏内的树突状细胞的激活情况;用体外混合淋巴细胞试验检测供体抗原特异性T淋巴细胞的增殖情况;排斥反应时及移植后150d行移植心病理切片检查。结果与non-DST组比较(移植心中位生存时间为7d),CD47-/-组移植心中位存活时间较长(中位生存时间为42d),但其存活时间明显短于CD47+/+组(中位存活时间150d,P0.01)。与CD47+/+组比较,CD47-/-组受鼠脾脏内表达CD11c+CD86+、CD11c+I-Adhi树突状细胞的百分比明显增加(P0.01,P0.05)。CD47-/-DST7d后,受鼠的供体反应性T淋巴细胞增殖明显增加,而CD47+/+组的供体反应性T淋巴细胞增殖明显受抑制(P0.01)。CD47-/-组移植心受排斥时,心肌组织内可见大量单个核细胞浸润,而CD47+/+组移植心术后150d时仍未见明显单个核细胞浸润,且与正常对照的心脏无明显差别。结论 DST细胞上CD47可以通过抑制受体树突状细胞激活及抑制供体抗原特异性T淋巴细胞反应的途径诱导免疫耐受。