- Created on Friday, 24 February 2012 16:25
Recently, several research institutes in Croatia have been investigating the genotoxic effects of occupational exposure to lead acetate in pottery-glaze ceramic workers. Lead is an important environmental chemical contaminant and has been used since ancient times. It enters the environment from natural and anthropogenic sources, as it is used in a variety of industrial processes.
Increased risk for occupational lead exposure occurs among pottery and ceramic industry workers. The major exposure pathways for workers are inhalation and ingestion of lead-bearing dust and fumes. This occupational exposure can be evaluated by means of biological monitoring, such as the comet assay performed on lymphocytes.
A recent study used 30 exposed workers and 30 matched controls, of which several biochemical parameters were measured. The genotoxic effects of lead exposure were evaluated by testing peripheral blood lymphocytes using the DNA diffusion assay, the micronucleus test and the comet assay.
All steps of the comet assay (preceding electrophoresis) were performed on ice to prevent erroneous DNA damage or repair and effects of metabolic processes. Furthermore, to avoid possible position effects during electrophoresis, two parallel replicate slides per sample were prepared, and each replicate was processed in a different electrophoretic run. Image analysis was performed using a Perceptive Instrument's comet assay image analysis system and as a measure of DNA damage, tail length, tail intensity and tail moment were selected. (For more information on data presentation and the combining of data sets, please read our Comet Assay IV reporting page.)
This study reported that pottery workers exposed to lead had significantly higher level of lead in the blood and, consequently, increased values of tail intensity during comet assay analysis, together with an increased frequency of apoptotic and necrotic cells, and frequency of micronuclei.
In conclusion, this study indicated that pottery workers exposed to lead show evidence of genotoxic activity in their lymphocytes. However, the comet assay appeared to be a less sensitive test compared to DNA diffusion and micronucleus tests. This could be due to a prompt DNA repair mechanism of the damage caused by lead exposure. This study has highlighted the importance of the concomitant use of at least two different biomarkers when estimating a genetic risk of exposure.
This case study is based upon:
Evaluation of genotoxic effects of lead in pottery-glaze workers using micronucleus assay, alkaline comet assay and DNA diffusion assay
V. Kašuba, R. Rozgaj, M. Milić, D. Želježić, N. Kopjar, A. Pizent, Z. Kljaković-Gašpić and A. Jazbec