Comparison of efficacies of allogeneic hematopoietic stem cell transplantations between different routes of administration in mice / 中国实验血液学杂志

ABSTRACT

When hematopoietic stem cells (HSCs) were administrated by intravenous infusion (IV), most of them were trapped in some nonhematopoietic organs as like lungs that had abundant blood capillaries. Only a small fraction of injected cells could home to the bone marrow, which reduced the engraftment of HSCs. The purpose of intra-bone marrow (IBM) transplantation was to facilitate the homing of HSCs directly. Based on the established murine model for allogeneic umbilical cord blood transplantation (UCBT) by IBM injection, the objective of this study was to compare the distribution of fetal and neonatal peripheral blood (FNPB) mononuclear cells (MNC) in vivo and the efficacy of HSCT by different routes of administration in mice. BALB/c recipient mice exposed to sublethal dose 60Co gamma-ray were transplanted with FNPBMNCs from C57BL/6 mice. Recipient mice were divided into six groups at random unilateral-IBM group; bilateral-IBM group; IV group; bilateral-IBM + IV group; irradiated control group and normal group. The distribution of CFSE-labeled FNPBMNCs in the recipients was observed in frozen sections of different organs or by flow cytometry. The survival rate, engraftment level, recovery of hematopoietic function and GVHD of recipient mice were studied. The results showed that infused by IBM route, FNPBMNCs mainly accumulated in the bone marrow (BM) cavity of the injected side tibia. Some of them could enter the BM of noninjected bones via blood circulation and few were trapped in the lung. Though same amount of FNPBMNCs were injected into recipient mice of unilateral and bilateral-IBM group, less cells could leak into peripheral blood or other tissues when transplanted by bilateral-IBM route. Therefore, in term of accelerating hemopoietic recovery, the injection of IBM route was better than IV route, especially bilateral IBM injection of HSCs, which neared the normal level of peripheral blood cells and colony-forming units of bone marrow nucleated cells at day 21 after transplantation, followed by unilateral-IBM group and bilateral-IBM + IV group. The percentages of H-2Db cell subsets in the three IBM groups were much higher than that in IV group. There was no significant difference of the engraftment level in the injected side tibia between the unilateral and bilateral-IBM group. When secondary transplantation was performed, the engraftment level in bilateral-IBM group was still much higher than that in IV group. At day 90, the survival rates of IBM groups were all > or = 80%, while that of IV group was only 50%. It is concluded that bilateral-IBM route can facilitate the homing of more HSCs, accelerate the engraftment of HSCs and hematopoietic reconstitution, which promoted the efficacy of IBM-HSCT.