混合细胞共微囊化对肝细胞功能的支持作用

目的观察大鼠肝细胞、转基因肝星状细胞株HGF／CFSC和／或大鼠骨髓来源Thy-1^＋β2M^-细胞（BDTC）共微囊化对肝细胞生物学活性的支持,及腹腔移植混合细胞微囊对急性肝衰竭大鼠肝功能的改善作用。方法利用微囊发生器制备含肝细胞或混合细胞的微囊,依微囊内包裹细胞种类不同,分为微囊化肝细胞组、微囊化肝细胞＋CFSC／HGF组）和微囊化肝细胞＋CFSC／HGF＋BDTC组,通过观察囊内细胞形态和体外培养测定培养液中白蛋白和尿素的分泌,判断各组囊内肝细胞活性和功能的维持;将90％肝大部切除所致的急性肝衰竭大鼠按照移植微囊种类不同分为空囊对照组和上述3个实验组（每组10只）,观察腹腔植入后不同时间大鼠的一般状况、存活时间、血生化改变、肝组织再生及微囊化移植物的组织学特征。结果与单独肝细胞微囊者相比,混合细胞微囊内肝细胞存活时间超过1倍,培养液中白蛋白分泌和尿素合成量明显增加（均P〈0．01）;与对照组相比,微囊化肝细胞或微囊化混合肝细胞移植后,急性肝衰竭大鼠的肝功能显著改善、存活率明显提高（10／10 vs 1／10）,其肝组织再生完全;移植21—42d时,部分微囊附着于肝脏表面并出现血管化,微囊表面存在不同程度的纤维化,微囊内仍有存活的细胞,以微囊化混合肝细胞组优于微囊化肝细胞组。结论混合细胞共微囊化能明显改善囊内肝细胞的存活寿命、形态和功能的维持,微囊化混合肝细胞腹腔移植对促进急性肝衰竭大鼠的肝功能恢复具有显著作用。

Sustainment of hepatocyte function with mixed cellular co-encapsulation

OBJECTIVE: To evaluate the effects of mixed microcapsules of hepatocytes mixed with hepatocytes, transgenic hepatic stellate cell strain (HGF/CFSC), and/or bone marrow derived Thy-1(+) beta(2)M(-) cells (BDTCs) to sustain liver function. METHODS: Three kinds of microcapsules containing hepatocytes, hepatocytes + CFSC/HGFs, or hepatocyte + CFSC/HGF + BDTC were prepared and cultured in conditioned culture fluids. The morphology of the microcapsules and the encapsulated cells were observed by microscopy. The supernatant was collected regularly to detect the secretion of albumin and urea. Forty Wistar rats underwent 90% hepatectomization to establish acute liver failure model. Six hours after the operation the rats were randomly divided into 4 groups to be intraperitoneally injected with one of the 3 kinds of microcapsules containing 3.5 x 10(7) hepatocytes as experimental groups (Groups II, III, and IV) or injected with blank microcapsule as control group. The behaviors of the rats were observed daily. Blood was collected from the eyeball at different time points to detect relevant biochemical indicators. Twenty-one and 42 days after the operation the rats were killed. Abdominal lavage was performed to collect the microcapsules to undergo microscopy. Liver specimens were colleted to undergo pathological examination. RESULTS: Severe liver failure occurred in the rats transplanted with blank microcapsules. Most of the rats in Groups II, III, and IV began to eat within 20 hours after hepatectomization. Nine of the 10 rats in the control group died within 48 hours after hepatectomization. Nine of the 10 rats of Group II survived a long time. All the rats in Groups III and IV survived till the end of experiment. In comparison with the supernatant of Group II, the contents of albumin and urea in the supernatants of Groups III and IV were significantly higher (all P < 0.01). The liver function indicators, ALT, AST, lactic dehydrogenase, and albumin worsened since one day after the operation. Five days after the transplantation of microcapsule, the above indicators showed remarkable improvement, and recovered to normal 7 days after. Twenty-one and 42 days after the transplantation regeneration was seen and edema was reduced in the livers in Groups II, III, and IV. Twenty-one days after the transplantation most of the microcapsules were still free in the peritoneal cavity in Group II. In Group III, most of the microcapsules aggregated around the portal vein, fibrosis at the surface of microcapsule to a certain degree was seen and surviving hepatocytes could be found inside the capsules 21 days after. Forty-two days after, vascularization of microcapsules was seen in Groups III and IV, especially in the latter group. CONCLUSION: Mature hepatocyte, transgenic liver nonparenchymal cells and/or BMSCs co-encapsulate transplantation effectively improve acute liver failure. The microenvironment created by CFSC/HGF and/or BDTC is propitious to the maintenance of capsulated hepatocytes' function and longevity.