Colonization and differentiation of transplanted embryonic stem cells in the irradiated intestine of mice.

Radiation-induced intestinal injury is a common complication in radiotherapy for the cancer located in abdomen or pelvis. However, there is no effective treatment for radiation-induced intestinal injury now. It is therefore important to develop new treatments for radiation-induced intestinal injury. In this study, we investigated whether embryonic stem (ES) cells could be transplanted directly into the radiation-damaged intestine and could colonize and differentiate into the intestinal epithelial cells. The intestines of female nude mice (ICR nu/nu) were irradiated at a single dose of 30 Gy, and were immediately transplanted with male 129/Sv-derived ES cells into the wall of the irradiated intestine by direct injection. The intestine was removed on days 13 to 27 after transplantation. The Y-chromosome DNA of transplanted ES cells in the irradiated intestine was determined by polymerase chain reaction. Colonization and differentiation of transplanted ES cells in the irradiated intestine were analyzed by histological and immunohistochemical methods with antibodies against stage-specific embryonic antigen-1, alpha-smooth muscle actin and cytokeratin AE1/AE3. The cells of donor origin were identified in the intestine of irradiated mice, and intestinal crypt-like structures were observed on day 13 after transplantation. Importantly, we observed that ES cells could differentiate into epithelial cells in the submucosa of irradiated intestine on day 13 and 27 after transplantation. These results suggest that transplanted ES cells could colonize and differentiate in the intestinal intestine. Such a new approach for damaged intestine with transplanted stem cells would be promising.