RESUMO
AIM:To study if low dose NaNO2 can induce the adaptive response of cultured Chinese hamster lung cells(CHL cells)to DNA damage.METHODS:Single cell gel electrophoresis technique was used to detect the DNA damage in CHL cells exposed to NaNO2 at different concentrations.CHL cells were pretreated with NaNO2 of concentrations of 0.01 mg/L,0.1 mg/L and 1 mg/L respectively.And the adaptive response to the toxicity of 1g/L NaNO2 was observed.The activity of polyADP-ribose polymerase(PARP-1) of CHL cells was inhibited with 3-aminobenzamide(3AB) before or after pretreated with low dose of NaNO2.And the changes of the adaptive response were observed.RESULTS:The rate of tailing cells was 7.87% when the cells were exposed to 1 g/L NaNO2 without pretreatment with low dose NaNO2.An extremely remarkable statistics significance(P0.05).The adaptive response could be blocked when the activity of PARP-1 was inhibited with 3AB before the low dose pretreatment,but could not be blocked when the activity of PARP-1 was inhibited after low dose NaNO2 pretreatment 6 h.CONCLUSION:NaNO2 of concentration that equals to or lowers than 0.1 mg/L can induce the adaptive response of cultured CHL cells to DNA damage caused by high dose NaNO2 through PARP-1 activation.And the dose of NaNO2 that can induce adaptive response might not cause the DNA damage.