Micronuclei Frequency in Lymphocytes and Antioxidants in the Blood of Traditional Limited-Resource Farm Workers Exposed to Pesticides

Chronic low-level exposure to synthetic pesticides is implicated in many health conditions that result from the induction of oxidative stress, including cytogenetic damage. The objective of this study was to assess the risk of genotoxicity using micronuclei (MN) formation in lymphocytes and to determine changes in blood antioxidants superoxide dismutase (SOD) in erythrocytes (E) and glutathione (GSH) in E and plasma (PL) in farm workers for six months during a growing season. Blood and urine samples were collected once a month for six months (June to November 2003) from farm workers (n = 15) and urban unexposed controls (n = 10). Lymphocytes from blood were separated by density gradient centrifugation using Histopaque and cultured using the standard technique. There was no significant difference in the cytokinesis blocked proliferation index (CBPI) of lymphocytes between the farm workers and the control group, but there was a 76% increase in average MN frequency in lymphocytes of the farm worker group (P ≤ 0.05). In addition, MN frequency peaked during August as compared to the other months and the controls (P ≤ 0.05). An 18% decline was observed in the activity of E-SOD in the farm worker group (P ≤ 0.05). GSH in E and PL were similar in both groups. These data suggest that the farm workers may be at a greater risk of developing genotoxicity due to continued exposure to pesticides, especially during the intensive growing season.

Key Words:

• Micronuclei
• Peripheral lymphocytes
• Farm workers
• Superoxide dismutase
• Glutathione

ACKNOWLEDGMENTS

We appreciate the support of Dr. Barbara Rall of the United States Department of Agriculture (USDA), Agriculture Research Service for this project. The authors are indebted to Dr. T.S. Kochhar for sharing his expertise. The authors also thank P. Rogers (phlebotomist) and students B. Gray and A. Okonny for their assistance, and appreciate the help of C. Petrey and E. Chavous in recruiting farm workers for this study.

Notes

∗Means in the same row are significantly different at P ≤ 0.05 as determined by one way analysis of variance.

^†HB = hemoglobin.