Abstract: Objective To assessed the ability of interleukin -12 (IL-12) to facilitate hematopoietic recovery from X-ray irradiation. Method BALB/c mice received different doses of recombinant murine interleukin -12 (rmIL-12) before 2 hours and after 24 hours of X-ray irradiation respectively. Blood was collected to test the blood profiles differences between pre-irradiation and post-irradiation. Results White blood cells of mice in all groups were decreased to the lowest level on day 4 after irradiation and then began to rise. On day 8 after irradiation, the number of white blood cells in rmIL-12 (200 ng per mice) treatment group was significantly higher than those of placebo saline group, 50 ng rmIL-12 treatment group and 2.5 μg rhG-CSF treatment group (P<0.001), red blood cells in all groups were decreased persistently and reached the lowest level on day 12. Starting from the 12th day, the number of red blood cells in each group began to recover. On day 12, the number of red blood cells in rmIL-12 (200 ng) treatment group was significantly higher than that of placebo saline group (P<0.001); platelets in irradiated mice demonstrated a downward trend within 8 days following irradiation, and administration had little effect on such decline. On day 12, platelets began to increase in all groups, but no significant difference was noted. Conclusion IL-12 can significantly promote hematopoietic recovery from X-ray irradiation induced damage. And this study provided an experimental basis for IL-12 in the clinical treatment of hematopoietic system damage.

Key words: IL-12, rmIL-12, X-ray, Hematopoietic system