Association between exposure to nitric oxide and changes in select molecular markers of health among men in the gold jewelry manufacturing industry

Gold jewelry workers are occupationally exposed to nitric oxide (NO) during the purification of gold. The present study involves the evaluations of chromosome aberrations (CA), micronucleus (MN) and comet assay in lymphocytes and identifies the influence of polymorphisms in DNA repair genes (XRCC1280Arg/His, XRCC1399Arg/Gln) among the gold jewelry workers occupationally exposed to nitric oxide (NO). Among the 84 samples undertaken for study, the non-exposed (categorized based only on age being group I <35years; group II ≥35 years) and exposed subjects (categorized based on age and work duration) constituted 42 subjects each. With increase duration of years of exposure, an increased level of chromosomal damage was observed. Likewise, a higher degree of chromosomal damage and MN was observed in exposed subjects of group II with a total CA of 8.07 ± 3.29 and MN of 10.61 ± 2.25 when compared to group I. Significant increases were also indicated with the overall CA frequency for the exposed subjects for chromatid, chromosome type aberrations and the MN/1000 binucleated cells in peripheral lymphocytes (p < 0.05) in comparison with non-exposed. The analysis of mean tail length of comet assay shows the DNA damage among the group II exposed subjects exhibits higher degree of chromosomal damage, indicating chronic exposure of NO causes the genetic modification, largely influenced by the polymorphic genotypes XRCC1280Arg/His (p < 0.001) and XRCC1399Arg/Gln (0.524). In conclusion, this result of work provides evidence for an apparent genotoxic effect associated with NO exposure. Our result reinforces the higher sensitivity of cytogenetic assays for the biomonitoring of occupationally exposed populations. So there is a strong need to educate those who work with potentially hazardous heavy metals about their adverse effects and highlight the importance of using protective measures.