OBJECTIVETo evaluate the hematopoietic reconstitution of implanted NOD/SCID mice, after intra-bone marrow cavity injection (iBM) of human umbilical cord blood (CB) mononuclear cells (MNCs).

METHODS24 female NOD/SCID mice were divided into different MNCs dosage iBM groups (3 x 10(6), 1 x 10(7), 3 x 10(7) cells), tail vein intravenous injection (iTV) group (3 x 10(7) cells) and control group (iBM of medium only). CB MNCs sorted by Ficoll-Hypaque were transplanted into left tibia bone marrow cavity of 6- to 8-week-old NOD/SCID mice, which were anesthetized and sublethally irradiated (270 cGy (137)Cs-gamma irradiation). The distribution of injected CB MNCs in noninjected right tibia of the same implanted mice was observed 24 hours after iBM. The establishment of hematopoiesis and the survival of mice were observed. BM cell surface CD marker expressions, dye Dil-CM tracing and human beta-actin from implanted mice were assessed 8 weeks after iBM or iTV.

RESULTSDil-CM marker could be detected on BM cells from noninjected right tibia 24 hours after iBM. Fourteen engrafted mice survived at the end of our study. Among them two, four and five were of iBM-1, iBM-2 and iBM-3 groups respectively, and one of control group and two of iTV group. White blood cell reconstitution was better in iBM mice than in iTV and control mice. There were human markers including CD45, Dil-CM and beta-actin DNA in the marrow cells from the human CB MNC engrafted mice.

CONCLUSIONThe preliminary results showed that hematopoiesis reconstitution by iBM was significantly better than iTV.