Abstract
Purpose: :
Bone marrow (BM)-derived stem cells are able to differentiate into various types of tissue resident cells. Previous studies revealed that BM-derived cells exist in mouse cornea and the majority of these cells were CD11b+ or CD11c+ immunocompetent cells. Although some of BM-derived cells in the cornea were negative for CD11b and CD11c, it remains elusive whether these cells are actually non-immunocompetent cells. The aim of this study is to clarify whether BM-derived cells can differentiate into non-immunocompetent cells in the cornea.
Methods: :
BM cells from C57BL/6 green fluorescent protein (GFP)-transgenic mice were intravenously injected into C57BL/6 wild type (WT) recipient mice that had been lethally x ray-irradiated (BMT mice). Four months after BM transplantation, the BMT mice were again lethally x ray-irradiated and received BM cells from C57BL/6 WT mice (2nd BMT mice). Three weeks later, the 2nd BMT mice were sacrificed and corneas and spleens were harvested for immunofluorescent microscopic and flow cytometric analyses, respectively.
Results: :
The percentage of GFP+ cells out of whole splenocytes was less than 1% in 2nd BMT mice. In contrast, many GFP+ cells were detected in the cornea of the 2nd BMT mice. These cells distributed abundantly in the limbus and less in the peripheral and central cornea. These cells existed in the stroma but not in the epithelial and endothelial layers.
Conclusions: :
Because most of GFP+ immunocompetent cells were depleted by the second x ray-irradiation, GFP+ cells in the cornea are considered to be non-immunocompetent cells. Thus, it appears that BM-derived cells differentiate into non-immunocompetent cells in the cornea.
Keywords: cornea: stroma and keratocytes • cornea: basic science