Abstract:

BACKGROUND: Bone marrow-derived stem cells have strong plasticity, but the mechanism that they participate in regeneration and renewal of tissue is still conflicting between transdifferentiation and cell fusion.
OBJECTIVE: To investigate the possibility and possible mechanism of bone marrow-derived stem cells involvement in the renewal of vascular endothelial cells in different organs through sex crossing bone marrow transplantation using mouse models of sexual mosaic.
METHODS: Female C57BL/6-green fluorescent protein (GFP) mice were used as donor mice, and male C57BL/6 mice were used as the recipient to establish bone marrow transplanted chimeric mice. The chimerism of bone marrow was assessed by flow cytometry. Twenty weeks after transplantation, frozen slide of the brain, kidney, liver, spleen, and heart were prepared and fluorescence in situ hybridization was applied to label the Y chromosome, then GFP expression and Y chromosome were observed using fluorescence microscope.
RESULTS AND CONCLUSION: The percent of GFP⁺ cell of bone marrow cells in the recipient was (7.48±1.38)% and (73.92±5.57)% at week 1 and week 4 respectively, indicating the success of sex crossing bone marrow transplantation model. In week 20, GFP expression was detected in vascular endothelial cells in the brain, kidney, liver, and spleen, and some cells also showed Y chromosome expression, indicating cell fusion occurred. No GFP expression was observed within the parenchyma of the brain and heart. Results have indicated that bone marrow-derived stem cells might have participated in the renewal of vascular endothelial cells in different organs through cell fusion.