[Effect of intra-bone marrow infusion of allogeneic mesenchymal stem cells on reconstruction of marrow mesenchymal stem cells in rat HSCT models].

This study was aimed to investigate the effect of intra-bone marrow (IBM) injection of allogeneic mesenchymal stem cells (MSCs) on reconstruction of bone marrow MSCs (BM-MSCs) in rats that received hematopoietic stem cell transplantation (HSCT), and to detect the donor MSCs in the hosts for clarifying the effect mechanism of donor MSCs. Wistar female rats conditioned with lethal dose 60Co gamma-ray irradiation were co-transplanted with F344 female fetal and neonatal peripheral blood (FNPB) and BrdU-labeled MSCs separated from bone marrow mononuclear cells of F344 male rats. The donor MSCs were infused by IBM injection in bilateral tibia or intravenous injection (IV), while the FNPB were all via IBM route. The survival rate, engraftment level of HSCs and recovery of BM-MSCs of recipients were monitored. The ratio of BrdU-labeled MSCs in recipient rats was calculated by immunofluorescence assay (IFA) and the Y chromosomes were examined by PCR. The results showed that the recipient rats of the two co-transplantation groups were all alive at day 60 after transplantation. There was no significant difference between these two groups on the survival rates or the engraftment levels of HSCs, but each of them was much better than that of the FNPB group. At day 30 after transplantation, the proliferation ability of recipients' BM-MSCs was still below normal, while that of the FNPB (IBM)+MSC (IBM) group was the best of all the experiment groups (p<0.01). At 60 days, the donor MSCs coexisted with host MSCs in only a few recipient rats examined by IFA, while the Y chromosomes could be detected in all the recipient rats in the two cotransplantation groups. It is concluded that the infusion of allogeneic MSCs can accelerate the recovery of HSCT recipients' BM-MSCs. The IBM route is safe and more effective than intravenous infusion.