Effect of nickel sulfate alone and with ultraviolet light on micronuclei frequency in cultured human lymphocytes

Comutagenic or cocarcinogenic activities have been reported between nickel compounds and UV light. The presence of micronuclei in a binucleated lymphocyte is regarded as an alternative to classical cytogenic methods for monitoring chromosomal damage. The present study aimed to detect this comutagenicity as regards micronuclei induction. Human peripheral lymphocytes were treated with different concentrations of nickel sulfate and/or with UV light at 200 and 1000 ergs/mm2. Cells have been cultured and 100 binucleated cells were counted and the micronuclei frequency recorded. The observed values for all concentrations of nickel sulfate combined with UV were less than expected for an additive response of two agents computed as the combined increase over the values of the control for the metal and UV alone. Caution is advised when interpreting cytogenic values in multiple exposures.