Figure 1.

Thirty-day survival test after a challenge dose of 7.5 Gy in C57BL/6N-WT mice. Effect of a priming dose of 0.5 Gy X-rays on a subsequent challenge dose of 7.5 Gy X-rays on mouse 30-day survival was verified in both female (A) and male (B) animals. The solid line denotes the animals (4 females and 4 males) that were untreated with TBI. The dotted line represents the animals (30 females and 30 males) that were irradiated with only the challenge dose at postnatal 8 weeks. The broken line stands for the animals (30 females and 30 males) that were primed with a dose of 0.5 Gy X-rays at postnatal 6 weeks followed by a challenge dose of 7.5 Gy X-rays at postnatal 8 weeks. Two asterisks (**) indicate statistically significant differences (P < 0.01) between the 2 groups that were compared.