Abstract: Objective To investigate the biological characteristics and related factors of mesenchymal stem cells (MSCs) under hypoxia and to extend the knowledge for repairing clinical tissue injury. Methods MSCs were cultured and exposed to the hypoxic condition in vitro. The cell properties were observed by immunofluorescence staining, RT-PCR were performed to investigate the expression of VEGF、bFGF、TGF-β and IL-1α, in order to explore the changes of MSCs under hypoxia from the aspects of cell differentiation, related factors and cell signaling pathways. Results Cultured under hypoxia for 24 hours, cells were observed under inverted microscope and survived well, and no significant changes of cell morphology and growth patterns were observed. Immunofluorescence and double immunofluorescence staining found out there was a tendency that MSCs cultured in hypoxia transform into endothelial cells, particularly vascular endothelial cells. The expression of VEGF, bFGF, TGF-βand IL-1αwere all up-regulated in MSCs exposed to the hypoxic condition, but a weak expression in MSCs cultured in normoxia. Conclusion Under the hypoxic condition, MSCs can differentiate into vascular endothelial cell, and expression of factors VEGF, bFGF, TGF-β and IL-1α, which can enhance the formation and growth of vascular, are all up-regulated, directly or indirectly accelerate the vascularization in tissue injury.

Key words: Mesenchymal stem cells, Gene expression, Vascularization, Hypoxia