小鼠自体肝脏星状细胞联合同种异体胰岛细胞移植延长移植物存活时间的研究

目的 研究小鼠自体肝脏星状细胞联合同种异体胰岛细胞移植的新方法对胰岛移植物存活时间的作用.方法 选择雄性BALB/c小鼠为胰岛移植模型的供者,雄性C57BL/6糖尿病小鼠为受者.随机将受者分为A、B两组.A组:仅采用供者的胰岛细胞移植;B组:采用受者的肝脏星状细胞(HSCs)与供者胰岛细胞混合后共同移植.术后定期测定受者尾静脉血的血糖含量.结果 B组受者胰岛移植物的存活时间明显延长,血糖含量维持正常的中位时间为66 d(30～180 d),而A组血糖含量维持正常的中位时间为11 d(9～15 d),两组比较,差异有统计学意义(P＜0.001).结论 受者肝脏星状细胞能延长共同移植的同种异体胰岛移植物存活时间.     

抗原特异性CD4+CD25+T细胞对同种异体胰岛移植影响及作用机制研究

目的:探讨抗原特异性CD4+CD25+Treg细胞免疫对同种异体胰岛急性移植排斥反应的影响和机制。方法:用MACS分选供体抗原特异性CD4+CD25+Treg细胞免疫糖尿病BALB/cByJ受体小鼠，以ICR小鼠胰岛为供体行同种异体胰岛移植。观察移植后小鼠的存活时间、移植前后外周血CD4+和CD8+T细胞亚群的变化和移植物中Th1/Th2细胞因子mRNA表达水平的变化。结果:抗原特异性Treg细胞联合胰岛移植组(C组)胰岛移植物平均生存期为(34.57±17.15)d，显著长于单纯胰岛移植组(B组)的(10.6±1.82) d (P<0.01)；移植后第3天，C组外周血CD4+/CD8+的值显著低于B组(P<0.01)；C组移植物中IL-10,TGF-β mRNA表达比B组显著增强。B组移植物中IL-1β，IL-2及IFN-γ mRNA表达明显强于C组。结论:抗原特异性CD4+CD25+ Treg细胞可通过调节Th2/Th1之间的反应平衡而延长同种异体胰岛移植物的存活时间。     

Sertoli细胞诱导大鼠肝内胰岛移植物免疫豁免的实验研究

目的 探究睾丸Sertoli细胞能否对肝内共移植的胰岛移植物提供免疫豁免作用以及共移植的睾丸Sertoli细胞最佳数量。方法将同种大鼠胰岛及不同数量的睾丸Sertoli细胞同时移植于糖尿病受体的肝内,观察移植物存活情况、胰岛功能、并检测移植物内胰岛素和Fas配体(FasL)表达以及浸润淋巴细胞凋亡情况。结果单纯胰岛移植组平均存活期为(5.6±0.8)d,同时与胰岛细胞在肝内共移植的睾丸细胞数增加至1×107个时,平均存活期为(41.4±4.61)d,明显延长(P<0.05),胰岛移植物中有大量表达FasL的睾丸细胞和表达胰岛素的胰岛细胞.在移植物周围有大量浸润的淋巴细胞凋亡。结论睾丸Sertoli细胞与胰岛细胞同时在肝内共移植,通过诱导局部豁免而延长胰岛移植物的存活时间,且同时共移植1×107个Sertoli细胞时效果最好。     

胸腺内胰岛移植实验研究

在小鼠胰岛移植模型上将BALB/c小鼠胰岛移植到C57BL/6小鼠胸腺,同时给予一次性腹腔注射抗胸腺细胞血清,胰岛移植物获得长期存活,而肾被膜下移植胰岛未能长期存活。再次植入供体BALB/c小鼠和NIH小鼠胰岛 到胰岛存活>100天的C57BL/6胸腺外肾被膜下,3周后BALB/c小鼠胰岛不发生排斥而第三者NIH胰岛移植后则发生排斥。证实诱导了对供体特异性无反应性,这表明胸腺作为一移植部位,明显优于肾被膜下(P>0.01)。     

肝星状细胞对同种异体胰岛移植物的保护作用

目的 研究小鼠肝星状细胞对同种异体胰岛移植物的保护作用.方法 将糖尿病小鼠随机分为三组,分别为糖尿病组、单纯胰岛移植组及与肝星状细胞共同移植组.单纯移植组于肾被膜下移植入同种异体胰岛300个;共同移植组移植入肝星状细胞(3×105个)与同种异体胰岛(300个)混合物.分别于移植术后监测受体小鼠血糖值及正常血糖维持时间;血糖正常一周后移植组及糖尿病组小鼠分别采血检测血清中TGF-β,TNF-α,IL-1β,IFN-γ的含量,同时取出移植物进行免疫组织化学检测.结果 术后共同移植组受体正常血糖维持时间为(23.75±8.96)d,单纯胰岛移植组受体正常血糖维持时间为(11.9±6.92)d,差异有统计学意义(P<0.05);三组受体血清中TNF-α、IL-1β、IFN-γ含量差异无统计学意义(P>0.05),共同移植组受体血清中TGF-β含量为(2292.31±5.87)pg/ml,单纯移植组为(1246.55±38.91)pg/ml,两组比较差异有统计学意义(P<0.05);病理学结果显示共同移植组胰岛素表达量大,并且在移植物周围有生物包膜形成.结论 在同种异体移植模型中,肝星状细胞可能通过高分泌TGF-β、局部形成包囊等方式保护胰岛移植物并延长其存活时间.     

吲哚胺2,3-双加氧酶在间充质干细胞诱导肾移植免疫耐受中的作用

目的研究探讨骨髓间充质干细胞(MSC)是否能够诱导肾脏移植物免疫耐受的产生以及吲哚胺2,3-双加氧酶(IDO)在MSC介导免疫调节反应中的作用。方法在BALB/c小鼠接受C57BL/6小鼠移植肾脏后24小时,C57BL/6小鼠来源的正常(wt)或IDO基因敲除(IDO-/-)的MSC(1×106)经静脉注入到移植受体中,分别作为wt-MSC治疗组和IDO-/--MSC治疗组,每组6只。以6只未注射的BALB/c移植小鼠受体为未治疗组。以移植物排斥反应所致小鼠死亡或术后100天设定为研究终点。长期存活的BALB/c肾移植受体在移植术后100天,接受来自C57BL/6供体或第三方移植物供体C3H(H-2k)小鼠的皮肤移植,监测移植皮肤情况。对3组小鼠进行移植物组织病理学观察,免疫组化评估肾脏组织Foxp3+细胞水平。用流式细胞技术进行抗原特异性抗体和细胞表型检测,用混合淋巴细胞反应(MLR)评估树突细胞(DC)和T细胞功能。结果本研究发现wt-MSC治疗可诱导受体产生同种异体移植物免疫耐受,表现为移植物病理检查结果正常、未发现抗原特异性抗体水平升高、免疫耐受受体中耐受性树突细胞(Tol-DC)数量显著增多等。同时,在免疫耐受的受体脾脏和肾移植物中均可发现大量CD4+CD25+Foxp3+调节性T细胞(Treg)。这些结果均提示Treg在MSC诱导免疫耐受中的重要作用。值得关注的是,经IDO-/--MSC处理的移植受体中,MSC丧失了其诱导同种异体移植物的免疫耐受的能力,肾移植物很快被排斥,同时机体移植物的排斥反应变化与未治疗组相同。结论由MSC分泌的IDO通过促进Treg的生成,在诱导肾脏移植免疫耐受中起着关键性的作用。本研究将为MSC在器官移植中的临床应用提供理论及临床转化依据。     

供体骨髓细胞输注诱导大鼠肢体移植免疫耐受

目的 探讨环磷酰胺(CP)加供体脾细胞输注联合供体骨髓细胞(DBMC)输注诱导大鼠肢体移植免疫耐受的效果及机制.方法选择25只雄性Wistar大鼠、25只雌性SD大鼠分别作为肢体移植的供体和受体.实验分为五组:A组:无处理对照组,B组:受体在肢体移植前给予供体脾细胞输注预处理;C组:受体在肢体移植前给予CP预处理,D组:受体在肢体移植前给予供体脾细胞输注加CP预处理,E组:受体在肢体移植前给予供体脾细胞输注联合DBMC输注加CP预处理,每组5只.建立肢体移植动物模型,诱导耐受后观察大鼠一般情况,移植肢体排斥反应出现时间及存活时间,通过混合淋巴细胞培养确定耐受状态,采用PCR检测嵌合体的形成.结果 E组肢体移植物的存活时间[(27.6±1.1)d]较A组[(6.8±0.4)d]、B组[(7.2±0.8)d]、C组[(7.8±1.3)d]、D组[(17.8±0.8)d]显著延长,差异均有统计学意义(P＜0.01).混合淋巴细胞反应E组特异性抑制率[(88.00±1.06)%]显著高于B组[(36.90±1.08)%]、C组[(37.90±0.95)%]和D组[(67.20±1.12)%],差异均有统计学意义(P＜0.01).E组嵌合体呈阳性.结论联合CP加供体脾细胞输注及DBMC输注可一定程度诱导大鼠同种异体肢体移植的免疫耐受,延长移植物存活时间.嵌合体的形成可能与免疫耐受的形成及维持有关.     

小鼠异位心脏移植血液循环重建模型的建立

目的 建立新的一种简单、稳定的小鼠腹腔异位心脏移植模型.方法 将供体心脏肝上下腔静脉与受体下腔静脉端侧吻合,供体升主动脉与受体腹主动脉端侧吻合.用C57BL/6J (H-2b)作供体和受体做同基因心脏移植,用C57BL/6J (H-2b)作供体BALB/C (H-2d)受体做同种异体心脏移植.结果 新方法血管吻合时间(21.3±1.6)min比传统方法吻合时间(28.5±1.4)min明显缩短,心脏复跳时间从(2.3±0.9)min降低到(1.4±0.5)min.同基因和同种异体移植的两种方法比较,1周生存率差异无统计学意义(P>0.05).结论 小鼠心脏移植新模型明显缩短移植物温缺血时间,有利于移植物长期存活.     

术前使用FTY720诱导小鼠对同种异体心脏移植物的耐受

目的　观察术前使用FTY72 0对小鼠同种异体心脏移植物存活时间的影响。方法　以小鼠颈部异位心脏移植为模型 ,供者为BALB/c小鼠 ,受者为C57BL/ 6小鼠。受鼠分为 4组 :A组为空白对照组 ;B组术前 3d至术后 1 1d每日管饲FTY72 0 ;C组手术当天至术后 1 4d每日管饲FTY72 0 ;D组仅在术前 3d至手术当天每日管饲FTY72 0。FTY72 0的剂量都为 3mg·kg- 1 ·d- 1 。结果　A组移植物中位存活时间 (MST)为 8d ;B组所有移植物存活时间均超过 2 7d ,有半数 (6/ 1 1 )移植物存活超过1 0 0d ;C组移植物存活时间显著延长 (MST =1 6d) ;D组移植物中位存活时间为 1 4d ,并有 1只超过1 0 0d。结论　术前使用FTY72 0可以延长同种异体心脏移植物的存活时间 ,诱导受者对同种异体心脏移植物的耐受     

第三方骨髓间充质干细胞对同种异体皮肤移植的影响

目的 探讨第三方骨髓间充质干细胞(bone marrow-derived mesenchymal stem cells,BMSCs)对同种异体皮肤移植的影响.方法 40只雌性C57BL/6和50只雄性BALB/C小鼠分别作为皮肤移植的供体和受体.将50只BALB/C小鼠随机分为5组,每组10只:空白对照组,直接进行皮肤移植;给予受体环磷酰胺组(Cyelophosphamide,CP组);给予受体SD大鼠BMSCs移植组(SD-BMSCs组);给予受体CP+SD-BMSCs移植组(CP+SD-BMSCs组);CM-DiI荧光标记组.CP+SD-BMSCs组给予大剂量CP腹腔注射,200 mg/kg,2 d,移植当天自受体小鼠尾静脉注射1×10~6个SD-BMSCs.检测项目包括:观察皮片存活时间、单向混合淋巴反应、组织HE染色、组织荧光镜检,流式细胞仪检测受体外周血单核细胞中SD-BMSCs的含量等.结果 CP+SD-BMSCs组皮肤移植物存活时间(14.5±1.9)d,空白对照组为(8.O±0.8)d,CP组为(11.1±1.4)d,SD-BMSCs组为(10.9±1.4)d,CP+SD-BMSCs组皮肤移植物存活时间明显比后3组延长(P<0.05).混合淋巴反应结果显示,BMSCs对淋巴细胞的增殖抑制作用存在量效关系.HE染色发现CP+SD-BMSCs组不但有血管生成,淋巴细胞浸润也较少.CM-DiI标记的SD-BMSCs能够在BALB/c小鼠体内存活30 d以上,SD-BMSCs组与CP+SD-BMSCs组外周血流式细胞仪均检测到SD-BMSCs.结论 BMSCs能够在异种受体体内存活较长时间;第三方BMSCs能够延长同种异体移植物的存活时间;BMSCs能够抑制异种T淋巴细胞的活化增殖.     

霉酚酸酯处理的供者树突状细胞在诱导同种小鼠心脏移植耐受中的作用

目的 探讨霉酚酸酪(MMF)处理的供音来源的树突状细胞(DC)在诱导免疫耐受中的作用。方法 同种小鼠异位心脏移植前经尾静脉注射培养7d的供音源未成熟DC或培养的同时以MMF处理的供者未成熟DC，观察移植心脏存活时间以及受鼠血清中TH1和TH2细胞因子的变化。结果 接受未成熟DC回输的受者移植心脏存活期较单纯移植组显著延长，而以MMF处理未成熟DC可使移植物的存活时间得到进一步延长，并且显著抑制了TH1细胞因子的产生。结论 MMF对比的功能成熟有显著的抑制作用，MMF处理的DC能够诱导针对移植供者的特异性免疫耐受。     

Gene therapy in transplantation: pathological consequences of unavoidable plasmid contamination with lipopolysaccharide.

Experimental studies evaluated the responses of murine cardiac graft recipients to high and low levels of lipopolysaccharide (LPS) contaminating plasmid DNA preparations. Immediately prior to transplantation, graft recipients were transfected by injecting the quadriceps muscles with plasmids that encoded the murine interleukin (IL)-4 gene and beta-galactosidase (beta-gal) gene. Graft recipients transfected with plasmids encoding only the beta-gal gene served as negative plasmid controls. Three groups of mice were transfected with plasmids containing high levels of contaminating LPS: (a) nontransplanted C57B1/6 mice, (b) C57B1/6 cardiac isograft recipients, (c) DBA/2 (H-2d)-->C57BL/6 (H-2b) cardiac allograft recipients. Unexpectedly, graft failure within 24 h was observed in IL-4 transfected isograft and allograft recipients, but not in mice transfected with the beta-gal gene alone. However, histopathological findings, for example, vascular cell adhesion moelcule-1 (VCAM-1) expression in cardiac grafts and mononuclear lung infiltration, were remarkably similar for both treatment groups and consistent with LPS-induced pathology. LPS assays were used to evaluate four different methods of plasmid purification for degree of LPS contamination. A successful strategy for reducing levels of LPS contamination was identified and transfection experiments repeated in cardiac allograft recipients receiving LPS inoculum that were minimized and standardized (6.4 EU/mouse) for all treatment groups. Despite receiving substantially lower levels of LPS, in all treatment groups there was persistent cardiac graft endothelial cell activation manifested by VCAM-1 expression and persistent, albeit less severe, lung pathology. We found that plasmid contamination with LPS was unavoidable and that even very low levels can alter immune responses in transplant recipients confounding data interpretation. Thus, it is imperative to account for LPS contamination in experiments utilizing plasmid DNA for gene transfer, especially in experimental models of immunity and inflammation.     

Quantitative assessment of angiogenesis and osteogenesis after transplantation of bone: Comparison of isograft and allograft bone in mice

We performed a vital microscopic study in mice bearing dorsal skinfold chambers to characterize microvascular perfusion and leukocyte/endothelium interaction and their effects on elongation and mineralization of neonatal isograft and allograft bone. Isograft (C57/BL to C57/BL) and allograft bone (C57/ BL to BALB/C) revascularized simultaneously. However, vascular perfusion and density were lower in allograft bone than in isograft bone. Leukocyte/endothelium interaction was the same in isograft and allograft bones. Revascularization was not detected in allograft bone transplanted to presensitized recipients. Moreover, in preexisting vessels at the trans plantation site, leukocyte/endothelium interaction was altered in allograft bone of presensitized recipients, despite a normal systemic leukocyte count. Femoral growth resulting from thickening of both epiphyses did not differ between experimental groups, however, mineralization occurred in isograft bone only, Isograft bone was histologically intact, allograft bone hypovital and allograft bone in presensitized recipients necrotic 12 days after implantation. Our findings suggest that graft incorporation or rejection is mediated by the microvasculature and that presensi-tizing of recipients accelerates rejection of allograft bone.     

Quantitative assessment of angiogenesis and osteogenesis after transplantation of bone: comparison of isograft and allograft bone in mice

We performed a vital microscopic study in mice bearing dorsal skinfold chambers to characterize microvascular perfusion and leukocyte/endothelium interaction and their effects on elongation and mineralization of neonatal isograft and allograft bone. Isograft (C57/BL to C57/BL) and allograft bone (C57/ BL to BALB/C) revascularized simultaneously. However, vascular perfusion and density were lower in allograft bone than in isograft bone. Leukocyte/endothelium interaction was the same in isograft and allograft bones. Revascularization was not detected in allograft bone transplanted to presensitized recipients. Moreover, in preexisting vessels at the transplantation site, leukocyte/endothelium interaction was altered in allograft bone of presensitized recipients, despite a normal systemic leukocyte count. Femoral growth resulting from thickening of both epiphyses did not differ between experimental groups, however, mineralization occurred in isograft bone only. Isograft bone was histologically intact, allograft bone hypovital and allograft bone in presensitized recipients necrotic 12 days after implantation. Our findings suggest that graft incorporation or rejection is mediated by the microvasculature and that presensitizing of recipients accelerates rejection of allograft bone.     

Comparison of successful and unsuccessful islet/Sertoli cell cotransplant grafts in streptozotocin-induced diabetic mice

Sertoli cells (SC) protect islet allografts from immune destruction in diabetic rodents. In this study, we examined the difference between successful and rejected islet/SC cografts in order to further improve this procedure for optimal extension of islet allograft survival. We cotransplanted 500 BALB/c islets with 1-8 million BALB/c SC under the kidney capsule of diabetic BALB/c, C3H-HeJ, and C57BL/6 mice. Cotransplantation of islets with up to 8 million SC was not detrimental to long-term islet graft function in syngeneic mice. However, large numbers of SC were detrimental to islet graft survival in allogeneic mice with the optimal dose for cotransplantation of 4 or 1 million SC in C3H-HeJ or C57BL/6 mice, respectively. Examination of successful grafts, from euglycemic recipients, revealed the presence of SC arranged in tubule structures with islets surrounding these tubules. Cellular infiltrate in successful grafts revealed CD4 T cells and macrophages along the periphery and within the grafts, and very few CD8 T cells. Conversely, examination of unsuccessful grafts, harvested from hyperglycemic recipients at the time of rejection, revealed the presence of SC arranged randomly with islets adjacent to the Sertoli cells, when present, and massive CD4 and CD8 T cell as well as macrophage cell infiltration. Prolongation of islet allograft survival appeared to be a function of SC transplant mass and recipient genetic background. A consequence of long-term graft acceptance is the formation of SC tubule structures, which may be an additional requirement for optimal protection of islet allografts.     

Interferon-gamma is not a universal requirement for islet allograft survival

BACKGROUND: Although many transplantation studies have implicated a graft-destructive role for T helper (Th)1 cytokines and a graft-protective role for Th2 cytokines, more recent studies have challenged this paradigm by showing that long-term allograft survival can actually require the presence of Th1 cytokines, such as interleukin 2 and interferon (IFN)-gamma. The purpose of this study was to examine the requirement for IFN-gamma in the induction of islet allograft acceptance after monoclonal antibody therapy targeting conceptually distinct molecular pathways: the costimulatory molecule CD154, the CD4 coreceptor, or the beta2 integrin lymphocyte function-associated antigen (LFA)-1 (CD11a). METHODS: Diabetic C57Bl/6 (B6; H2b) mice were grafted with fully MHC mismatched BALB/c (H2d) islets, or reciprocally, diabetic BALB/c mice underwent transplantation with B6 islets and were treated with anti-CD154, anti-CD4, or anti-LFA-1. RESULTS: When IFN-gamma gene knockout mice were used as graft recipients, the requirement for IFN-gamma in allograft survival was found to be highly conditional, depending on both the host strain and the induction therapy used. In both strain combinations studied, anti-CD154 was effective in the presence or absence of IFN-gamma, whereas anti-CD4 lost therapeutic potential in the absence of this cytokine. Alternatively, the requirement for IFN-gamma for allograft prolongation by anti-LFA-1 therapy was noted only in B6 transplant recipients. CONCLUSIONS: IFN-gamma is not always requisite in islet allograft survival but rather varies according to the molecular target of induction therapy and the genetic background of the transplant recipient.     

Transplant Islets Into the Pinna of the Ear: A Mouse Islet Transplant Model

BackgroundIslets transplanted under the ear skin would allow easy observation of the graft response and survival in vivo. This research was designed to establish an efficient mouse islet transplant model to probe the dynamic cellular interplay in vivo.MethodsGreen fluorescent protein transgenic mice and BALB/c mice were used as donors and recipients. All recipients were divided into 6 groups of 6 mice each. First, we treated the transplant recipients, including diabetes induction, autologous epididymal fat pad, and MATRIGEL transplant to the ears. Then, 1. we transplanted isolated islets to the ear/ear with fat/ear with MATRIGEL; and 2. transplanted islets with collagen + basic fibroblast growth factor or islets with collagen + vascular endothelial growth factor. Mice in the control group received a sham transplantation with phosphate buffer saline. All recipients were then observed for 30 days with blood glucose (BG) monitoring. Finally, ears were removed with graft on day 28 for histologic examination.ResultsIt was suggested that transplant of islets alone could not correct hyperglycemia. Fat, MATRIGEL, collagen, and growth factors have the similar function to form a microenvironment conducive to islet survival. The effect of islet transplantation for correcting hyperglycemia of the fat modification group was better than other groups (P < .05). BG could be normalized, and living islets were detected by anti-insulin immunohistochemistry.ConclusionsTransplant islets into the ear with transplanted autologous fat is the optimal way which can be used to analyze the allograft response in vivo and track cell population and migration using labels by confocal microscopy.     

缺乏可诱导共刺激信号的供体特异性输血促进受体鼠T细胞凋亡的体内研究

目的 探讨缺乏可诱导共刺激分子(ICOS)/B7h信号的供体特异性输血(DST)对异基因小鼠心脏移植术后T细胞(Tc)凋亡的影响.方法 按陈氏方法建立小鼠颈部异位心脏移植模型,术后统计各组移植物的存活时间.实验分3组,异基因组:分别以BALB/c和C57BL/6为供、受体,不予治疗;同基因组:供、受体均为C57BL/6,不予治疗;治疗组:以BALB/c和C57BL/6为供、受体,给予治疗.通过流式细胞术检测受体鼠外周血CD8+ICOS+Tc亚群比例以及受体鼠引流淋巴结中CD8+Tc的凋亡情况.结果 与异基因组比,治疗组中心脏移植物存活时间明显延长[(84.4±29.1) d vs.(7.0±0.8) d,P＜0.01].与异基因组比,治疗组外周血CD8+Tc亚群无明显缩减,而在CD8+ICOS+Tc亚群中,治疗组中显著低于异基因组[(7.5±2.0)% vs.(14.0±3.0)%,P＜0.05].与异基因组比,治疗组受体移植术后7 d引流淋巴结中CD8+Tc凋亡比例显著上调[(19.5±5.1)% vs.(8.7±3.1)%,P＜0.05].结论 通过ICOS/B7h信号的供体特异性输血预处理可以诱导引流淋巴结中CD8+Tc凋亡,这与受体外周血中CD8+ICOS+Tc亚群变化相关,可能在耐受的诱导过程中起重要作用.