大鼠骨髓间质干细胞体内诱导肝星状细胞的凋亡

Rat bone marrow mesenchymal stem cells induce hepatic stellate cells apoptosis in vivo

背景:骨髓间质干细胞治疗肝纤维化的疗效已得到很多实验的证实,但其机制仍不明确。目的:实验观察骨髓间质干细胞移植后肝星状细胞的凋亡情况,初步探讨骨髓间质干细胞治疗肝纤维化的机制。方法:连续8周皮下注射CCl4诱导大鼠肝纤维化。造模成功后,20只大鼠随机分为实验组及对照组,每组10只。实验组经尾静脉注射骨髓间充质干细胞,对照组经尾静脉注射DMEM培养液。于移植前,移植后第3,7天分别处死大鼠,取其肝脏行羟脯氨酸的检测,苏木精-伊红染色及masson染色,免疫组织化学检测α-SMA及α-SMA+TUNEL双染反映肝星状细胞活化及其凋亡情况。结果与结论:造模8周后,大鼠肝脏羟脯氨酸含量明显升高,病理呈进展性肝纤维化表现。移植7d后,实验组大鼠肝脏羟脯氨酸含量明显降低,肝纤维化有所缓解,而对照组的肝纤维化程度继续加重。免疫组织化学显示,CCl4注射8周后,α-SMA阳性细胞大量增生,移植后第7天,实验组α-SMA阳性细胞明显少于对照组(P<0.05)。移植后第3天,实验组肝星状细胞凋亡明显较对照组增加(P<0.05)。结果提示,骨髓间质干细胞移植有治疗肝纤维化的作用。骨髓间质干细胞诱导肝星状细胞凋亡可能是其治疗肝纤维化的主要机制之一。

BACKGROUND： It is reported that bone marrow mesenchymal stem cell （BMSC） transplantation might be a promising treatment for liver fibrosis. But the mechanism is still unclear. OBJECTIVE： To observe the hepatic stellate cells apoptosis induced by BMSC transplantation, and to study the mechanism of BMSC in treating hepatic fibrosis in vivo. METHODS： CCl4 subcutaneous injection was performed to induce rat liver fibrosis. After 8 weeks of CCl4 injection, 20 rats which underwent successful model establishment were randomly divided into experimental group and control group, 10 in each group. The experimental group received MSC transplantation via tail vein injection, and the control group were given DMEM instead. The rats were killed and the livers were harvested at three time point, the day of MSC transplantation, 3 days after transplantation, and 7 days after transplantation. The hydroxyproline content was detected by HE and Masson staining, and the expression changes of α-smooth muscle actin （α-SMA） proteins were determined using immunohistochemistry. The apoptosis of hepatic stellate cells were determined by α-SMA and TUNEL （terminal dUTP nick-end labeling） dual-staining. RESULTS AND CONCLUSION： After 8 weeks of CCl4 injection, the hydroxyproline content increased and histology indicated progress of liver fibrosis. At 7 days after MSC transplantation, the hydroxyproline in the liver was decreased, and the liver fibrosis was alleviated in the experimental group but aggravated in the control group. Immunohistochemistry indicated that α-SMA positive cells were increased at 8 weeks after CCl4 injection. At day 7 after transplantation, α-SMA positive cells in the experimental group were significantly less than control group （P 0.05）. At 3 days after transplantation, the hepatic stellate cells apoptosis in the experimental group was significantly aggravated compared with control group （P 0.05）. This suggested that MSC transplant was an effective treatment for liver fibrosis. MSC inducing hepatic stellate cells apoptosis may be one of the mechanisms.