In vivo multimodal microscopy for detecting bone-marrow-derived cell contribution to skin regeneration.

Bone-marrow (BM)-derived cells have been shown to be capable of aiding skin regeneration in vivo by differentiating into keratinocytes. However, the conditions under which this occurs are not fully understood. Characterizing innate mechanisms of skin regeneration by stem cells in vivo is important for the area of stem cell biology. In this study, we investigate the use of novel in vivo imaging technology for characterizing the contribution of BM-derived cells to regeneration of the epidermis in mouse skin in vivo. In vivo imaging provides the ability to non-invasively observe the spatial positions and morphology of the BM-derived cells. Using a GFP BM-transplanted mouse model and in vivo multimodal microscopy, BM-derived cells can be observed in the skin. Our in vivo imaging method was used to search for the presence and identify the 3D spatial distribution of BM-derived cells in the epidermis of the skin under normal conditions, following wound healing, and after syngeneic skin grafting. We did not observe any evidence of BM-derived keratinocytes under these conditions, but we did observe BM-derived dendritic cells in the skin grafts. In vivo multimodal imaging has great potential for characterizing the conditions under which BM-derived cells contribute to skin regeneration.