Effect of human umbilical cord mesenchymal stem cell-secretion on proliferation and apoptosis in hepatocytes

Abstract

Objective To investigate the effect of human umbilical cord mesenchymal stem cell paracrine substance on proliferation and apoptosis of liver cells in vitro. Methods Mesenchymal stem cells (MSC)were separated from human umbilical cord with type Ⅳ collagenase and trypsogen digestion method and cultured in vitro. The human umbilical cord mesenchymal stem cells-conditioned medium(MSC-CM) which contain paracrine substance of human umbilical cord mesenchymal stem cells (HUCMSC) was prepared. Hepatocytes were isolated from SD rats by low concentration collagenase perfusion procedure. There were three groups in the experiment, control group, 2% MSC-CM group and 8% MSC-CM group. The proliferation of normal hepatocytes were assayed with MTT method. We detected the urea and albumin level in culture supernatant to assay the hepatocyte function under different concentration MSC-CM. Hepatocytes were induced for apoptosis by Actinomycin D and tumor necrosis factor alpha (TNF-α),and the apoptosis effect of different concentration MSC-CM was assayed with LIVE/DEAD Viability/Cytotoxicity Kit. Results The MTT assay showed that the absorbance of 2% MSC-CM group was significantly increased (P＜0. 01), and the urea and albumin levels of 2 % MSC-CM group were also significantly increased when compared with control group(P＜0. 01).LIVE/DEAD Viability/Cytotoxicity Kit revealed that hepatocyte survival rate of 2 % MSC-CM group was increased when compared with control group(P＜0. 05), there were no significant differences in above-mentioned experiments when 8% MSC-CM group compared with control group. Conclusion The low concentration MSC-CM could stimulate normal hepatocyte proliferation, inhibit impaired hepatocyte apoptosis and improve hepatocyte function. Key words: Umbilical cord mesenchymal stem cell; Paracrine; Hepatocyte; Regeneration; Apoptosis