RESUMO
Objective To explore if the occupational exposure to low dose thorium could induce adaptive response in peripheral lymphocytes.Methods 40 individuals.who exposed to thorium and rare earth mixed dust(exposure group) or control in Baotou Steel Plant, were selected, and chromosome aberrations were analyzed.Then the peripheral blood samples were irradiated in vitro with 2 Gy60Co γ-rays,and unstable chromosome aberration or DNA stand breakage analysis using single cell gel electrophoresis was performed. Results The dicentrics before 2 Gy exposure in exposure group was higher than that in control(P>0.05). But the dicentries after 2 Gy exposure in exposure group was lower than that in control,but not significantly (P>0.05).The tricentrics in exposure group was significantly lower than that in control(U=3.1622, 0.0ol<P<0.002).The DNA strand breakage in control group was significantly higher than that in exposure group(t=25,P<0.001).Conclusions Occupational exposure to low dose thorium could induce the adaptive response on chromosome aberration and DNA strand breakage in peripheral lymphocytes.