Redistribution of bisbenzimide Hoechst 33342 from transplanted cells to host cells

Identification of transplanted cells within host tissue is an important component of many transplantation experiments. In this study, Schwann cells labelled with the fluorochrome bisbenzimide (Hoechst 33342, H33342) and transduced with the lac-Z gene were introduced into normal white matter and their distribution was examined 2 h, 24 h and 4 weeks after transplantation. At 2 and 24 h following transplantation, H33342-labelled cells were more widely distributed than lac-Z-labelled cells in both longitudinal and transverse directions. By 4 weeks following transplantation, no lac-Z-labelled cells could be found. However, H33342-labelled cells were observed in and around the glial scar. Therefore, labelling of host cells by transfer of H33342 dye from transplanted cells has to be considered whenever this dye is used as a transplant marker.