TABLE 4.

Radiation Protection of Fancd2^−/− Marrow Stromal Cells by ROS-Scavenging Nitroxide, JP4-039

Stromal cell line	JP4-039	D0	ñ
Fancd2−/−	0	1.45 ± 0.05 P1 = 0.0021	4.99 ± 0.65 P1 = 0.0040
Fancd2−/− + JP4-039	preirradiation	1.73 ± 0.10 P2 = 0.0237 P3 = 0.0458	5.10 ± 2.00
Fancd2+/+	0	1.80 ± 0.08	8.33 ± 0.73
Fancd2 +/++ JP4-039	preirradiation	2.33 ± 0.23 P1 = 0.0177	5.37 ± 1.44
Hematopoietic cell line		D0	ñ
Fancd2−/−	0	1.56 ± 0.25	3.46 ± 1.99
Fancd2−/− + JP4-039	preirradiation	1.44 ± 0.17	3.49 ± 1.10
Fancd2+/−	0	1.87 ± 0.21	3.85 ± 1.57
Fancd2+/− + JP4-039	preirradiation	2.09 ± 0.28	2.65 ± 0.57
Fancd2+/+	0	1.31 ± 0.10	1.00 ± 0.10
Fancd2+/+ + JP4-039	preirradiation	2.3 ± 0.3 P = 0.043	1.00 ± 0.10

Notes. In vitro survival curves were performed with bone stromal and hematopoietic progenitor cells lines. Cells were incubated in 10 μM JP4-039 for 1 h before exposure as described in the literature (9, 19), then irradiated with doses ranging from 0–8 Gy, plated in 4-well tissue culture plates, incubated for 7 days at 37°C, and stained with crystal violet. Colonies >50 cells were counted and analyzed using a linear-quadratic model or single-hit, multi-target model (9, 19). D₀ and ñ are expressed as mean ± SD of at least 3 experiments. P < 0.05 were significant and are bold. P1 = comparison with Fancd2^+/+ control unirradiated; P2 = comparison with Fancd2^−/− unirradiated; and P3 = comparison with Fancd2 ^+/+ JP4-309 (preirradiation).