Objective      To determine the expression of interleukin-12 (IL-12) in the cultured peritoneal macrophages (Mφ) and in mice after electromagnetic radiation.       Methods      Kunming mice and primarily cultured Mφ were radiated in 900 MHz electromagnetic field with an average power density of 90 mW/cm

2

for 20 and 10 min respectively. RT-PCR was used to detect the expression of IL-12p40 in the spleen and culture

d Mφ at mRNA level. ELISA was employed to measure the levels of IL-12p70 in the serum and the M φ supernatant. Western blotting and EMSA was used to test IκB-α expression and transcriptional activity of NF-κB respectively in the cultured Mφ. The intervention effect of pyrrolidinedithiocarbamate (PDTC)

a NF-κB specific inhibitor

on the change of IL-12 expression after electromagnetic radiation was also observed.       Results      In 5 d after radiation

the expression level of IL-12p40 mRNA and the content of IL-12p70 in the serum reached a peak with a increase of 9.32% and 259.76% respectively

significantly higher than those in normal control (P0.05). The content of IL-12p70 and the expression of IL-12p40 mRNA in mice returned to normal level in 11 d after irradiation. The content of IκB-α in cultured Mφ was reduced to a minimum in 8 h after radiation with a drop of 27.97%

significant lower than that of normal group (P0.01). In 12 h after acute radiation

the expression of IL-12p40 mRNA in cultured Mφ and the content of IL-12p70 in culture medium was increased reached a peak

significantly higher than those in the normal control group (P0.01). After acute radiation

the NF-κ B-probe binding activity was increased

and reached to the strongest in 8 h after radiation. PDTC resulted in a decrease in enhanced IL-12 expression induced by electromagnetic radiation

with an inhibitory rate of (83.43±7.58)%.       Conclusion      Acute exposure to 900 MHz electromagnetic radiation increases the expression of IL-12 by up-regulating NF-κB activity.