Low-dose radiation-induced hormetic effect on hematopoietic reconstitution

To investigate the effects on hematopoietic reconstitution of recipient mice receiving bone marrow cells (BMC) of donor pre-exposed to low-dose radiation (LDR).

BMC were irradiated in vitro at various low-dose X-rays radiation. Tritiated thymidine ((3)H-TdR) incorporation was adopted to measure the proliferation of the BMC in vitro, and then the optimal radiation doses were selected for further study in vivo. Irradiated recipient mice (7.5 Gy) were infused by BMC exposed to 6 and 8 cGy. The counts of recipients' peripheral blood cells (PBC) and bone marrow mononuclear cells (BMMNC) were monitored at the 5th, 10th, 15th, and 30th day after BMC infusion. The colony-forming units in the recipient spleens (CFU-S) were calculated at the 10th day after infusion.

Exposed to 6 and 8 cGy, BMC demonstrated significant proliferative activities in vitro. When the recipient mice receiving BMC pre-exposed to low dose radiation (6 and 8 cGy), the counts of white blood cell (WBC), BMMNC and CFU-S were consistently higher than those in control.

BMC of donor irradiated by LDR in vitro may facilitate the hematopoietic reconstitution of the recipient mice.