BIOMONITORING OF WORKERS EXPOSED TO LEAD - GENOTOXIC EFFECTS, ITS MODULATION BY POLYVITAMIN TREATMENT AND EVALUATION OF THE INDUCED RADIORESISTANCE

A population monitoring study was performed, by using the micronucleus (MN) assay in human peripheral lymphocytes, to investigate whether oc cupational exposure to lead is genotoxic to workers. In addition to th e exposed workers group, two more groups were studied, an external gro up from a factory without exposure to lead and an internal control gro up, from the same factory as the exposed workers, but that were not di rectly exposed to lead. Measures of lead levels at working place and i n blood were calculated, and blood samples were collected to carry out a MN study. The results from these studies indicate that the blood fr om workers directly exposed contained high levels of lead, compared wi th the other groups, and a significant increase in the frequency of bo th the total number of MN and the number of binucleated cells carrying MN appeared. In addition, a study on the antimutagenic effects of a p olyvitamin rich diet was conducted by measuring the frequency of MN af ter the workers had a four month daily intake of a polyvitamin-polymin eral complex. These results clearly show a significant reduction of th e MN frequency evaluated after this treatment, obtaining values that w ere even lower than those obtained in the internal control group. Fina lly, a challenge assay was carried out to determine response to gamma- radiation as indication of any kind of radiosensitivity or radioresist ance. The results of this experiment did not show any significant vari ation in the increase of the frequency of MN after challenge irradiati on in the lead exposed workers; nevertheless this increase was signifi cantly reduced in the sample obtained after the polyvitamin treatment indicating a radioresistance response. (C) 1998 Elsevier Science B.V. All rights reserved.