大鼠肝脏再生过程中细胞标志物演变与骨髓细胞增生

Changes of bone marrow cells and cell markers In regenerated liver after partial hepatectomy in rats

目的:为研究大鼠在部分肝切除术后肝再生过程中是否存在骨髓细胞的增生与动员以支持肝脏再生过程,以及肝卵圆细胞(hepatic oval cells,HOC)在体内细胞标志物的演变过程. 方法:SD(Sprague-Dawley)大鼠81只,随机分为3组: 2/3部分肝切除组(partial hepatectomy,PHx)、2/3部分肝切除加2-乙酰氨基芴(2-acetylaminofluorene, 2AAF)预处理组(PHx+2AAF)及假手术组,每组分为9小组(n=3),分别于术后1,2,4,6,8,12,16, 20,24 d采集大鼠骨髓细胞及再生肝组织;采用percoll密度梯度液分离骨髓细胞中的单个核细胞,并用流式细胞分析技术检测单个核细胞中CD34+,CD45+细胞比例; 采用冰冻组织切片技术进行再生肝组织切片,并用免疫荧光组织化学染色检测再生组织中与CD34共表达的部分造血干细胞、肝卵圆细胞及肝细胞的细胞标志物Thy1.1,CD45,CK19,vimentin,AFP,Alb. 结果:在PHx模型中,流式细胞检测结果显示大鼠骨髓单个核细胞中CD34+及CD45+细胞在术后2,4, 6 d与对照组相比增高(分别为2.774±0.166 vs 1.903±0.044,P=0.016<0.05;3.164±0.056 vs 1.862±0.057, P=0.002<0.01;2.708±0.160 vs 1.897±0.149,P= 0.032<0.05),免疫荧光组织化学染色结果示在肝组织中第4 d发现少量CD34,CD45共表达细胞,但未检出其他共表达的细胞标志物.在PHx+2AAF模型中, 流式细胞仪检测结果示CD34+及CD45+细胞于术后2, 4 d与对照组相比增高(分别为2.472±0.141 vs 1.903±0.044,P=0.020<0.05;2.985±0.120 vs 1.862±0.057, P=o.008<0.01),荧光免疫组织化学染色显示其再生肝组织中与CD34共表达的抗原Thy1.1,CK19,Alb, AFP,vimentin等存在动态演变:在标志物出现过程中,Thy1.1最早出现,随后可检出AFP,vimentin, CK19,而Alb最后检出;在标志物的消失过程,则Thy1.1, Alb,CK19最早消失,随后AFP,vimentin未检出. 结论:大鼠在急性肝损时的肝再生过程中存在骨髓CD34+与CD45+的细胞增生现象,再生肝组织中与CD34共表达抗原的动态演变可能反映肝卵圆细胞在体内的产生与分化的演变过程.

AIM: To investigate the replication and mobilization of bone marrow (BM) cells in support of liver regeneration, and the alteration of hepatic oval cell markers in the regenerated liver. METHODS: In the Sprague-Dawley (SD) rats receiving 2/3 partial hepatectomy (PHx) with or without 2-acetylamin-ofluorene (2AAF) treatment, CD34+, CD45+ BM cells were measured by flow cytometry. The changes in cell markers of hemopoietic stem cells, hepatic oval cells and hepato-cytes in the regenerated liver were determined by fluorescence immunohistochemistry at the indicated time points after PHx. RESULTS: The numbers of CD34+ and CD45+ BM cells were increased in both PHx (2-6 d) and PHx+2AAF (2-4 d) rats. CD34 and CD45 co-expressing cells were observed in the regenerated liver sections, which was significantly increased after 2AAF treatment. In the PHx+2AAF rats, the cell markers co-expressed with CD34 exhibited dynamic changes: Thy1.1 appeared first, followed by AFP, vimentin, CK19, and Alb; while Thy1.1, Alb, and CK19 disappeared earlier than AFP and vimentin. CONCLUSION: CD34+, CD45+ BM cells replicate during the liver regeneration in rats. The changes of the cell markers co-expressed with CD34 reflect the in vivo development of hepatic oval cells.