悬滴培养诱导大鼠骨髓间充质干细胞分化为肝样细胞

目的: 与平板培养比较,探讨悬滴三维培养对大鼠骨髓间充质干细胞(rMSCs)肝样分化的诱导效应。方法: 对rMSCs进行悬滴培养,以肝细胞生长因子(HGF)作为诱导因子,同时设定平板培养诱导和非诱导对照组,在培养第7、14和21 d后,通过RT-PCR法和免疫荧光技术检测白蛋白(ALB)、甲胎蛋白(APF)和角蛋白(CK-18)在mRNA和蛋白水平上的表达情况,并通过ELISA检测培养液上清中ALB的分泌。结果: HGF悬滴培养的rMSCs形成球状三维结构,内部呈现空囊样结构,大量细胞聚集在球体外侧面;在第7 d就出现ALB和CK-18的强阳性表达,而AFP则表达较弱。HGF培养的单层rMSCs直到第14 d才出现ALB、AFP和CK-18 mRNA的弱阳性表达,蛋白表达则在第21 d才呈现阳性。ELISA检测到HGF悬滴培养后rMSCs能够胞外分泌ALB,与正常和平板培养诱导组比较差异显著(P<0.01)。结论: 悬滴培养为rMSCs创造一种球形三维培养微环境,在HGF的诱导作用下,rMSCs横向分化为肝样细胞。

Hepatic differentiation of mesenchymal stem cells derived from rats in three-dimensional microenvironment formed by hanging drops

AIM: To establish an optimal differentiated three-dimensional microenvironment formed by hanging drops for the high efficiency of hepatic differentiation from rat mesenchymal stem cells(rMSCs).METHODS: rMSCs were cultured in the hanging drops, which provided a three-dimensional microenvironment, for 21 days in the presence of hepatocyte growth factor(HGF, 20 μg/L). The expression of albumin(ALB), alpha-fetoprotein(AFP) and cytokeratin-18(CK-18) was detected by RT-PCR and immunofluorescence staining at 7th, 14th and 21st days. The secretion of albumin in the culture supernatants was measured by ELISA. RESULTS: rMSCs were aggregated in spheroid with a tubiform medium altitude in the center. In rMSCs cultured in the hanging drops with HGF, the expression of albumin, AFP and CK-18 was all detectable by RT-PCR and immunofluorescence staining at 7th day. The production of albumin in the cells cultured in the hanging drops with HGF was 50.25±5.32, 55.03±7.45 and 54.92±3.18(ng·dish^-1·d^-1) at 7th, 14th and 21st days, respectively, significantly higher than that in the cells in the plate cultivation with or without HGF induction at corresponding time points(P<0.01).CONCLUSION: In the presence of HGF, rMSCs are induced to differentiate into hepatocyte-like cells cultured in the hanging drops, where the three-dimensional spheroidal cultures are promising microenvironment for hepatic transdifferentiation of MSCs.