DNA Damage and Repair in Cells of Lead Exposed People

Background: One of the main sources of occupational exposure to lead in Colombia is in workers of battery industries and lead smelters. Genotoxic studies in human populations exposed to this metal have had conflicting results; this type of study has not been reported in Colombia.

Methods: Genotoxic effects of lead were studied in blood cell samples from workers of electric battery factories exposed to lead compounds. Single strand breaks and interference with DNA repair processes after an in vitro exposure of x-rays (300 cGy) were analyzed using the Comet Assay. The battery workers (n = 43) and 13 people not occupationally exposed to lead compounds who were selected as a control group, were classified into four categories according to their blood lead level.

Results: A significant difference was observed in DNA damage before the x-rays exposure (basal) between the lowest and highest categories of lead (mean DNA migration 55.6 micro and 85.9 micro, respectively). Additionally, a significant difference in DNA migration was also found immediately after irradiation between the lowest and highest lead categories (mean DNA migration: 199.8 micro and 317.8 micro respectively). The DNA migrations at different times after irradiation did not show a significant difference among the different lead levels.

Conclusions: We concluded that although the single strand breaks following irradiation were not affected by blood lead concentration, the metal seems to sensitize the cells to damage induced by other genotoxicants.