[PAHs exposure and its association with oxidative stress and neurotransmitter levels in coal miners]

Objective: To learn the investigate of polycyclic aromatic hydrocarbons (PAHs) and to explore the association between PAHs exposure and oxidative stress' neurotransmitter levels in coal miners. Methods: A cross-sectional survey was conducted in 652 coal miners (239 in the underground first line group, 280 in the underground auxiliary group and 133 in the surface group) from April to June 2017. The levels of urinary monohydroxy PAHs metabolites (OH-PAHs) , oxidative stress and neurotransmitters in blood were determined. A linear regression model was used to evaluate the correlation between OH-PAHs and oxidative stress' neurotransmitter levels. The mediating role of oxidative stress between urinary OH-PAHs and neurotransmitters change was assessed by mediation analysis. Results: The levels of 2-hydroxynaphthalene (2-NAP) 、2-hydroxy uorene (2-FLU) 、1-hydroxypyrene (1-OHP) in urine OH-PAHs of coal miners in different workplaces were significantly different (H=33.64, 9.63, 26.82, P<0.01, =0.008, <0.01) . The levels of neurotransmitters [5-hydroxytryptamine (5-HT) , norepinephrine (NE) , epinephrine (E) , dopamine (DA) , acetylcholine (Ach) , acetylcholinesterase (AChE) ] and oxidative stress [malondialdehyde (MDA) (F=36.81, 15.58, 79.16, 179.58, 33.48, 67.63, 4.96, P<0.01) ] in the blood of three groups of coal miners were significantly different. After controlling the potential confounding factors, NE content was negatively correlated with 2-FLU level, and AChE activity was also negatively correlated with 1-OHP level (β=-134.99, 95% CI: -250.74~-19.23, P=0.02; β=-0.80, 95%CI: -1.54~-0.05, P=0.036) . Positive correlation was found between Ach content and 9-hydroxyphenanthrene (9-PHE) level, AChE activity was also positively correlated with 2-NAP level and 9-PHE level (β=0.96, 95%CI: 0.26~1.64, P=0.007; β=1.78, 95%CI: 0.75~2.82, P=0.001; β=0.77, 95%CI: 0.07~1.47, P=0.031) . In addition, superoxide dismutase activity was correlated with 1-OHP level and AChE activity (β=0.32, 95%CI: 0.02~0.62, P=0.034; β=-0.23, 95%CI: -0.43~-0.02, P=0.032) . Mediation analysis indicated that 1-OHP level may directly affect AChE activity (P<0.05) . Conclusion: The level of PAHs in underground coal miners is relatively higher, and may lead to changes of neurotransmitter levels. The mediating effect of oxidative stress has not been observed.