Survival rates in MRL/lpr mice treated by various methods.

(A) MRL/lpr mice irradiated with 5.5 Gy × 2 were injected with BMCs via the peripheral vein (intravenously, IV), via the portal vein (PV), or into the bone marrow cavity (intra–bone marrow, IBM). As a negative control, the mice irradiated with 8.5 Gy received BMCs via the IV. Numbers in parentheses represent the numbers of mice used in each group. Statistical analyses were carried out by a log-rank test:P < .001, 5.5 Gy × 2 + IBM versus 5.5 Gy × 2 + PV. (B) MRL/lpr mice irradiated with 5 Gy × 2 were injected with BMCs via the IV, via the PV, or via the IBM. Furthermore, the mice that had been irradiated with 4.5 Gy × 2 were injected with BMCs via the IBM.