小鼠胚胎干细胞在同种正常肝脏中的定向分化

DIRECTIONAL DIFFERENTIATION OF EMBRYONIC STEM CELLS IN THE SAME RACE NORMAL LIVER

目的研究小鼠胚胎干细胞在正常肝脏微环境中的迁移、分化及对正常肝组织的影响。方法分离小鼠生殖腺嵴获取胚胎干细胞,体外扩增、5-溴-2-脱氧尿嘧啶核苷(BrdU)标记后经尾静脉注入正常小鼠体内。于注射后2、4周取肝脏,连续冷冻切片,采用苏木精-伊红染色、免疫荧光双染色和PAS染色检测移植细胞在肝内的分布、清蛋白表达和糖原合成情况,显微计数分析肝细胞的增殖状态。结果移植2周,受体鼠肝脏内均可见散在分布的大而圆的BrdU和清蛋白双阳性细胞,PAS染色呈强阳性反应;体积小的BrdU阳性细胞,清蛋白表达呈阴性。移植4周,单位面积内BrdU阳性细胞数量较2周时减少,PAS着色较2周时浅,糖原颗粒细小、分布均匀,肝细胞的形态比较规则,但体积变大,胞核大而松散,单位面积的肝细胞数量较正常肝脏减少,肝小叶结构与正常鼠比较无显著改变。结论静脉移植的胚胎干细胞可以迁移至正常肝脏,在肝脏微环境中分化为肝细胞,并刺激正常肝细胞增殖。

Objective To investigate the transfer and differentiation of mouse embryonic stem cells（MESC）in normal liver microenvironment and its effect on the liver tissue. Methods Dissecting mouse genital rige to take embryonic stem cells,and amplified in vitro.The cells were then labelled with 5-bromo-2-deoxyuridine（BrdU）and injected into a normal mouse through caudal vein.Two and four weeks after the injection,the liver was taken for continuous frozen sections.Employing HE staining,double immunofluorescence and PAS staining to detect the distribution of transplanted cells,expression of albumin,and glycogen synthesis,and using microscopic count to analyze the proliferation of the liver cells. Results In two weeks after the transplantation,diffused distribution of large-and-circular BrdU and albumin cells could be seen in liver tissue of recipient rats,with strongly positive reaction to PAS staining,for small-volume BrdU-positive cells,the expression of albumin was negative.In four weeks of transplantation,the number of BrdU-positive cells in a unit area was less than that in two weeks,the PAS reaction was lower,glycogen particles became small and well distributed,the form of liver cells was regular,but the volume became bigger,and the number of liver cells in a unit area was less than that in normal liver. Conclusion Intravenous transplantation of embryonic stem cells can migrate to normal liver and differentiate to liver cells in hepatic microenvironment and activate multiplication of normal liver cells.