Human umbilical cord blood stem cells applied in therapy for ionizing radiation injury

Since the events of ionizing radiation damage increasingly, the human healthy are threatened by radiation. With the development of cells regeneration, stem cells applied in therapy for radiation injury become a hotspot in recent years. Then we are aimed to study on experimental animals to human umbilical cord blood stem cells of ionizing radiation-induced hematopoietic injury. The 80 mice were randomly divided into normal group, radiation group, treatment group, strengthen group. Beside normal group, other groups were given 1 hour of 1 Gy radiation. Radiation group does not do any processing after radiation while treatment groups and strengthen group were given the stem cells by tail vein of mice (230IU/g dose). After 24h the strengthen group was given the stem cells again. All mice were sacrificed in 2d, 3d, 7d, 14d for blood routine examination and flow cytometry. The radiation group, treatment group, strength group that their white blood cells, red blood cells, lymphocytes, mononuclear cells, hemoglobin count dropped significantly after 1Gy radiation. Compared with normal group that there were significant differences (p<0.05). The treatment group and strength group that their white blood cells, red blood cells, lymphocytes, monocytes and hemoglobin counts were significantly higher than radiation group and normal group and showed significant differences (p<0.05). Compared with normal group, the radiation group, treatment group and strength group that their CD4+ cells, CD4+/CD8+ cells ratio significantly higher after radiation, the differences were significant (p<0.05). After the injection of stem cells from human umbilical cord blood, the treatment group and strength group CD4+ cells, CD4+/CD8+ cells ratio significantly lower than normal group, there were significant differences (p<0.05). This study indicates that human umbilical cord blood stem cells contribute to the recovery of hematopoietic system after irradiation injury.