To analyze the hematopoietic reconstitution in the mouse model of haploidentical hematopoietic stem cell transplantation when using umbilical cord blood cells as the third party cells.

The CB6/F1 mice were selected as the donor and the BALB/C mice were selected as the receptor. All the recipient mice were infused with donor stem cells after myeloablative with Co60 to establish the mouse model of the haploidentical hematopoietic stem cell transplantation. Forty recipient mice were equally divided into the experimental group and the control group. The mice in the control group were infused with donor mice-derrived haploidentical hematopoietic stem cell, and the mice in the experimental group were infused with umbilical cord blood cells and donor mice-derrived haploidentical hematopoietic stem cell. Blood collection by tail snipping in the viable recipient mice was performed at intervals of + 7, + 14, + 21, + 28, + 50 days after transplantation and then the assay of white blood cell, hemoglobin and blood platelet were performed to evaluate the hematopoietic reconstitution. One mL peripheral blood was obtained when the mice were sacrificed. The proportion of Y chromosome was dected by fluorescence in situ hybridization and then the proportion of chimerism was calculated. The test results of white blood cell, hemoglobin and blood platelet between the 2 groups were compared by t test, and the proportion of chimerism were compared by chi-square test. P<0.05 was considered statistically significant.

The white blood cell counts at + 14 days after transplantation between the experimental group and the control group were (8.4±2.6)×10⁹/L and (3.8±1.0)×10⁹/L respectively, which had statistical significance (t=6.968, P<0.05), while no statistical signicance was found at other time points. No statistical significance was found between the 2 groups for hemoglobin. The blood platelet counts at + 7d, + 14d after transplantation between the experimental group and the control group were (125±40)×10⁹/L and (64±15)×10⁹/L, (282±47)×10⁹/L and (163±41)×10⁹/L respectively, which had statistical significance (t=6.366 and 8.093, P<0.05), while no statistical signicance was found at other time points.

The recovery of peripheral blood white blood cell and blood platelet in the mouse model of haploidentical hematopoietic stem cell transplantation was faster with the help of umbilical cord blood cells infusion.