同种异体骨髓间质干细胞移植在大鼠肝内的定居能力

背景:骨髓间充质干细胞具有极强的自我复制能力和多向分化潜能,但当体外分离培养的骨髓基质干细胞移植到体内后,其分布和定居情况不明,这关系到骨髓基质干细胞是否可以作为靶细胞治疗应用于临床。目的:探索绿色荧光蛋白标记的大鼠骨髓间质干细胞(MSCs),经不同途径移植到同种异体大鼠,其定居于肝脏的能力。设计:析因设计。单位:广东省第二人民医院普外科/中山大学博士后科研基地,南方医科大学珠江医院普通外科,中山大学附属第三医院器官移植科。材料:实验于2003-01/2004-12在解放军第一军医大学基础部药理教研室完成。选取清洁级成年SD大鼠36只,随机分为5组:CCL4 门静脉移植组(6只)、门静脉移植对照组(6只)、CCL4 尾静脉移植组(6只)、尾静脉移植对照组(6只)、混合组(12只)。方法:①从大鼠骨髓中分离培养获取骨髓间充质干细胞,以绿色荧光蛋白进行标记,体外扩增后,以细针移植骨髓间充质干细胞悬液,移植量为0.5mL/100g。②CCL4 门静脉移植组:骨髓间充质干细胞移植前3d,每天按20g/L的CCL42.5mL/kg体质量灌胃饲养,首次计量加倍,标记的骨髓间充质干细胞从门静脉移植。门静脉移植对照组:骨髓间充质干细胞移植前正常饲养,标记的骨髓间充质干细胞从门静脉移植。CCL4 尾静脉移植组:骨髓间充质干细胞移植前3d,每天按20g/L的CCL42.5mL/kg体质量灌胃饲养,首次计量加倍,标记的骨髓间充质干细胞从尾静脉移植。尾静脉移植对照组:移植前正常饲养,标记的骨髓间充质干细胞从尾静脉移植。混合组:前4组条件下,各设2只大鼠移植未标记的骨髓间充质干细胞;另设CCL4喂养3d和正常喂养大鼠各2只,不行骨髓间充质干细胞移植。③于移植后的第3,7天,通过荧光定量PCR检测各组移植的骨髓间充质干细胞在大鼠肝脏的表达。主要观察指标:①骨髓间充质干细胞的分离纯化、体外扩增及表型鉴定结果。②绿色荧光蛋白标记骨髓间充质干细胞结果。③移植同源异体骨髓间充质干细胞后大鼠的生长情况观察。④各组肝脏组织中绿色荧光蛋白阳性DNA数的定量检测结果。结果:实验选取SD大鼠36只全部进入结果分析。①Percoll梯度分离液分离大鼠骨髓,所获得的细胞传代、扩增后,形态呈基本一致的梭性。细胞表面不表达CD34与CD45,而表达CD29,CD44,CD90等骨髓间充质干细胞的表面标志,是骨髓中区别于造血干细胞的另一群处于未分化状态的非定向干细胞。②骨髓间充质干细胞转染24h后即可见发绿色荧光的细胞。48～72h阳性细胞明显增多,强度增强,高倍视野下转染率达20%～30%,多为明亮的绿色荧光的细胞。作为对照的骨髓间充质干细胞中未发现发绿色荧光的细胞。③所有大鼠从不同途径移植标记或未标记的同源异体骨髓间充质干细胞后,第1天精神、食欲差,少活动;移植后第2天基本恢复正常饮食和精神,各组大鼠之间无明显差异。④除混合组外,其余各组于移植术后第3,7天,肝脏内均可检测到含绿色荧光蛋白阳性细胞。且CCL4 门静脉移植组、CCL4 尾静脉移植组肝脏组织中的绿色荧光蛋白阳性DNA数显著高于门静脉移植对照组、尾静脉移植对照组升高(P<0.05)。结论:干细胞定居于肝脏的时间与细胞数量可能与肝脏是否受损有关,与移植途径关系不密切。正常动物肝脏未受损情况下,干细胞可定居于肝脏,定植的细胞量与移植途径、移植后时间相关。

Capacity of colonizing to the liver after allografting of mesenchymal stem cells in rats

BACKGROUND: Meseuchymal stem cells (MSCs) have extremely strong self-duplication ability and multidirectional ifferentiation potential. When bone marrow stromal cells (BMSC) are isolated and cultured in vitro, implanted in vivo, the distribution and colonization are still unclear, which is concerned with whether BMSC can be usedas target cells in clinic.OBJECTIVE: To explore the capacity of colonizing to the liver after allografting of green fluorescent protein (GFP) labeled MSCs of rats by different approaches.DESIGN: Factorial design.SETTING: Department of General Surgery, Second People's Hospital of Guangdong Province, Postdoctoral Workstation of Sun Yat-Sen University;Department of General Surgery, Zhujiang Hospital, Southern Medical University; Department of Organ Transplantation, Third Hospital Affiliated to Sun Yat-Sen University.MATERIALS: The experiment was performed at the Staff Room of Pharmacology, Basic Department, First Military Medical University of Chinese PLA from January 2003 to December 2004. A total of 36 clean adult SD rats were selected and randomly assigned into 5 groups: CCL4 plus portal vein transplantation group (n=6), portal vein transplantation control group (n=6), CCL4 plus caudal vein transplantation group (n=6), caudal vein transplantation control group (n=6) and mixed group (n=12).METHODS: ① MSCs were obtained from rat marrow and labeled with GFP. After amplifying in vitro, MSCs suspension was implanted with thin needle, with the volume of 0.5 mL/100 g. ②CCL4 plus portal vein transplantation group: In 3 days before MSCs transplantation, the rats were administrated with 20 g/L CCL4 2.5 mL/kg by gastric perfusion every day. The dose was double at the first time. Labeled MSCs were implanted from portal vein. Portal vein transplantation control group: Before transplantation the MSCs were bred commonly, and the labeled MSCs were implanted from portal vein. CCL4 plus caudal vein transplantation group: In 3 days before MSCs transplantation, the rats were administrated with 20 g/L CCL42.5 mL/kg by gastric perfusion every day. The dose was double at the first time. Labeled MSCs were implanted from caudal vein. Caudal vein transplantation control group: Before transplantation the MSCs were bred commonly, and the labeled MSCs were implanted from caudal vein. Mixed group: On the basis of the former 4 groups, 2 rats were implanted with non-labeled MSCs; Another 2 rats fed with CCL4 for 3 days and normal feed were established, without MSCs transplantation. ③At days 3 and 7 after transplantation expression of transplanted MSCs in liver of rats of each group were examined with fluorescent quantitative PCR.MAIN OUTCOME MEASURES: ①Results of MSCs isolation, purification, in vitro amplification and phenotype identification, ②result of GFP-labeled MSCs, ③observation of growth of rats following allografting of MSCs, and ④result of quantitative identification of GFP positive DNA amount in hepatic tissues of each group.RESULTS: Totally 36 experimental SD rats were involved in the result analysis. ①Percoll gradient separating medium was applied to isolate bone marrow of rats. The obtained cells were transferred and amplified,and then mostly showed coincident shuttle shape. Cells did not express CD34 and CD45, but CD29, CD44 and CD90 of MSCs, which were noncommitted stem cells in non-differentiating status that were different from hemopoietic stem cells in bone marrow. ②The green fluorescent cells appeared 24 hours after MSCs transfection. From hour 48 to 72 the number of positive cells significantly increased, with strong intensity.The transfection efficiency was 20%-30% under high-power field, and most of the cells were with green fluorescence. But green fluorescent cells did not appear in the MSCs cells as control. ③After allografting of labeled or non-labeled MSCs of rats with different approaches, at day 1 the rats were listless with bad food appetite, less mobilization; At day 2mostly of them had normal diet and mood, but there was no significant difference in rats of each group. ④The rats in each group with the exception of mixed group had green fluorescent protein positive cells in liver at days 3 and 7. The number of green fluorescent protein positive DNA was higher in liver tissues in the CCL4 plus portal vein transplantation group and CCL4 plus caudal vein transplantation group than in the portal vein transplantation control group and caudal vein transplantation control group (P＜0.05).CONCLUSION: Duration and amount of stem cells colonizing in liver may be associated with liver injury, while not related to the implantation approach. In normal animals with uninjured liver the stem cells can colonize in liver, and the amount is associated with transplantation approach and post-transplantation duration.