[Experiment study of efficacy on hematopoietic reconstitution and GVHD prophylaxis after mesenchymal cell infused by intra-bone marrow cavity or intravenous in rat BMT models].

OBJECTIVE: To observe the in vivo distribution of mesenchymal stem cells (MSCs) after administrated by intra-bone marrow (IBM) or intravenous (i.v.), and compare the effects on hematopoiesis reconstitution and GVHD in rat BMT models. METHODS: (1) MSCs from male Wistar rats marked with CFSE were injected into the bone marrow cavity (IBM) or the vein (i.v.) of recipient rats, and observed the distribution of MSCs in vivo. (2) Allogeneic BMT model of Fischer344 rats (RT1A(1)) to Wistar rats (RT1A(u)) was established. The recipient rats were exposed to 8 Gy of gamma irradiation 1 day before transplantation. The 6 groups were (1) IBM group [IBM-injection of MSCs + IV-injection of bone marrow cells (BMC)]; (2) IV group (i.v.-injection of MSCs (i.v.) + i.v.-injection of BMC); (3) BMT group (only i.v.-injection of BMC); (4) MSCs control group (only i.v.-injection of MSC); (5) normal control group and (6) irradiation control group. RESULTS: (1) After i.v.-injection, large numbers of the MSCs lodged in lungs while small numbers in the peripheral blood, liver, thymus and spleen, and a few marked MSCs could be seen in bone marrow. After IBM injection, most cells distributed in long bones and those lungs were less than that in i.v. group. (2) Co-transplantation of MSCs (IBM/IV) could accelerate the recovery of hematopoiesis, including the recovery of WBC, hemoglobin and platelet, and in IBM-injection was more effective in the recovery of hematopoiesis than that in i.v. group. (3) Incidence rate of GVHD in BMT group was 42% (3/7), and no GVHD occurred in co-transplantation groups. (4) Recovery of CFU-Mix and CFU-MSCs could be seen at 21st and 30th day after transplantation in co-transplantation groups, and IBM-injection was more effective than i.v.-injection. CONCLUSION: (1) IBM-injection results in most MSCs distributed in long bones. (2) MSCs improve the survival rate after BMT. (3) Co-transplantation of MSCs accelerates the recovery of hematopoiesis and reduces the morbidity of GVHD. (4) MSC promotes reconstitution of hematopoietic cells and bone marrow MSCs in recipient rates and the effects of MSCs administrated via IBM is more effective than via i.v.