Oxidative Stress in Workers Occupationally Exposed to Lead

Abstract

Lead (Pb) is a pervasive and common environmental toxicant which has caused serious occupational diseases globally, and now a major public health challenge in Nigeria. The present study was designed to assess the status of blood lead levels (BLLs) and plasma markers of oxidative stress in individuals occupationally-exposed to lead. Thirty–eight lead exposed workers, comprising, eighteen (18) battery chargers (BC), ten (10) spray painters (SP) and 10 (ten) mechanics (MC) were recruited for this study after an informed consent. They were artisans (aged between 25 and 55 years) who have practiced their professions for a period of 17 to 25 years. The control group consisted of fifteen clinically healthy volunteers (CT). Blood Lead Levels (BLL) and antioxidant and markers of oxidative stress: superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), malondialdehyde (MDA), nitric oxide (NO), total antioxidant potential (TAP) and total plasma peroxides (TPP) were determined in them, using atomic absorption spectrophotometer and spectrophotometry methods respectively. Statistical analysis was done using the student’s t-test and ANOVA. The BLLs increased significantly in only BC and SP but not in MC when compared with controls. Specifically, BLLs were of the order: BC (5.5 folds) > SP (4 folds) > MC (1.5 folds), although there was no significant difference between the blood lead levels in MC (10.60±2.55μgPb/dl) and CT (8.51±4.55μgPb/dl). The mean values of plasma MDA contents were significantly (p<0.05) higher in all lead-exposed workers (BC, SP and MC) when compared with the controls (CT). The mean values of plasma Total Plasma Peroxide (TPP) and Oxidative Stress Index (OSI) were significantly (p<0.05) increased in BC, SP and MC when compared with the controls (CT) while there were no significant (p>0.05) changes in the mean values of NO in BC, SP and MC when compared with the controls (CT). The mean values of plasma antioxidant markers CAT, SOD and GSH were significantly (p<0.05) reduced in BC, SP and MC when compared with the controls. These findings show that lead plays an active role in the generation of reactive oxygen species and oxidative stress in workers occupationally- exposed to lead and that adjuvant antioxidant therapy may be needed to avert the consequences of oxidative stress.