Potential in the Diagnosis of Oxidative Stress Biomarkers in Noninvasive Samples of Urine and Saliva and Comparison with Serum of Persons Exposed to Crystalline Silica

Background: Prolonged exposure to crystalline silica (CS) (SiO2) dust enhances the production of reactive oxygen species. In many studies, oxidative stress has been measured in the serum of workers exposed to SiO2 dust. Aims: We investigated the body fluids such as urine, saliva, and serum, which can provide very good results for assessing the health status of workers’ exposures to SiO2 dust. Materials and Methods: The oxidative stress biomarkers were evaluated in serum, urine, and saliva of 21 workers who were exposed to SiO2 silica crushing factories in the Hamadan city at the west of Iran as a case group and 28 controls. Results: The level of malondialdehyde in serum, urine, and saliva was significantly higher than that in case group compared to controls (22.19 ± 8.70, 9.86 ± 5.43, and 9.41 ± 7.31 nmol/L vs. 7.30 ± 2.22, 6.79 ± 3.21, and 3.93 ± 3.73 nmol/L, respectively). In addition, the total antioxidant capacity in urine (0.23 ± 0.06 vs. 0.29 ± 0.08 mmol/L), as well as catalase in the serum and saliva of case group was lower than that compared to control group (5.46 ± 1.56 and 1.32 ± 0.55 IU/L vs. 12.55 ± 5.72 and 2.32 ± 1.53 IU/L, respectively). Conclusions: The current study indicated that chronic exposure to SiO2 affects significantly on the oxidative stress biomarker levels in serum, urine, and saliva in persons exposed. Furthermore, SiO2 leads to the induction of oxidative stress and decreases the activity of the antioxidant enzyme.