Abstract: Objective The purpose of this experiment was to investigate the effect of mesenchymal stem cells (MSC)-derived exosomes (MSCs-Exo) on the proliferation and activation of human hepatic stellate cells, e.g. LX-2 cells. Methods The MSCs-Exo were purchased and identified by electron microscopy observation and NanoFCM measurement. The LX-2 cells were stimulated with transforming growth factor-β1 (TGF-β1) at 5 μg/L, 10 μg/L and 20 μg/L concentration, and the α-SMA and COL1A1 mRNA and their proteins were detected by RT-PCR and Western blot. The activated LX-2 cells were intervened by MSCs-Exo at 50 μg/mL, 100 μg/mL at 200 μg/mL for 24 h. The LX-2 cell proliferation was detected by MTT assay. Results The morphological appearance and the particle sizes of MSCs-Exo revealed by transmission electron microscopy and NanoFCM accorded with requirement, and the MSCs-Exo positive marker proteins, CD9 and CD63 were positive, with GM130 protein negative; the α-SMA and COL1A1 mRNA and their protein expression in activated LX-2 cells by TGF-β1 stimulation were significantly increased and positively correlated with TGF-β1 concentration; the α-SMA and COL1A1 mRNA level and their protein expression were highest when the TGF-β1 induction at concentration of 20 μg/L; in the MSCs-Exo-100 and MSCs-Exo-200-intervened activated LX-2 cells, the proliferation viability of cells were significantly reduced compared with in the control (all P<0.0001); the α-SMA and COL1A1 mRNA and their protein expression in TGF-β1-activated LX-2 cells with different concentrations of MSCs-Exo intervention, e.g. at 50 μg/mL, 100 μg/mL and 200 μg/mL, were significantly decreased compared with in the control (P<0.001); the proliferation activities of LX-2 cells intervened by MSCs-Exo-100 and MSCs-Exo-200 were significantly decreased compared to that in the control cells (P<0.0001). Conclusion The MSCs-Exo could inhibit TGF-β1-induced proliferation and activation of LX-2 cells in vitro, and needs further investigation.

Key words: LX-2 cell, Mesenchymal stem cells-derived exosomes, Transforming growth factor-β1, Cell proliferation, Activation, In vitro