Benzo[a]pyrene-induced neurobehavioral function and neurotransmitter alterations in coke oven workers.
OBJECTIVE
To study alterations in neurobehavioral function and neurotransmitter levels in coke oven workers occupationally exposed to benzo[a]pyrene (B[a]P) and explore possible biomarkers of B[a]P neurotoxicity.


METHODS
176 coke oven workers occupationally exposed to B[a]P and 48 warehouse workers (controls) were investigated by questionnaire. Emotional and cognitive function was investigated using the WHO/NCTB. B[a]P concentrations in the working environment, concentrations of monoamine and amino acid neurotransmitters, and levels of urinary 1-hydroxypyrene (1-OH-Py) were assayed by HPLC. Spectrophotometry was used to determine choline neurotransmitter concentrations.


RESULTS
Airborne B[a]P concentrations were higher in the coke oven plant than in the controls' workplace, and 1-OH-Py levels were significantly increased in coke workers compared to controls (p=0.000). Digital span and order digital span scores indicated that learning and memory were significantly decreased in coke oven workers (p=0.006). Concentrations of norepinephrine (NE), dopamine, 5-hydroxytryptamine and homovanillic acid were lower, while levels of 5-hydroxyindoleacetic acid were higher in the exposed group compared to controls; the difference in NE was significant (p=0.000). Aspartic acid and gamma-aminobutyric acid levels were significantly decreased in coke oven workers compared to controls (p=0.004 and p=0.004). Acetylcholine (Ach) concentration was four- to fivefold greater in coke oven workers than in controls, while acetylcholine esterase (AchE) activity was significantly decreased (p=0.000 and p=0.012). Statistical analysis showed that digital span and order digital span scores were negatively correlated to Ach and positively correlated to AchE.


CONCLUSIONS
Occupational B[a]P exposure may reduce coke oven workers' neurobehavioral function and monoamine, amino acid and choline neurotransmitter levels. Moreover, Ach and AchE correlated with neurobehavioral function; AchE has poor specificity, but Ach is a potential biomarker of B[a]P neurotoxicity in coke oven workers.
Department of Occupational Health, School of Public Health in Shanxi Medical University, 56 Xin Jian Nan Lu, Taiyuan, China. niuqiao55@163.com
Qiao
Q
Niu
Hongmei
H
Zhang
Xin
X
Li
Meiqin
M
Li
D000328:Adult; D000395:Air Pollutants, Occupational / Q000009:adverse effects*; D001564:Benzo(a)pyrene / Q000633:toxicity*; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D003077:Coke / Q000633:toxicity*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D018377:Neurotransmitter Agents / Q000737:chemistry*; D016273:Occupational Exposure / Q000009:adverse effects*; D011084:Polycyclic Aromatic Hydrocarbons / Q000652:urine*; D011721:Pyrenes / Q000032:analysis; D011795:Surveys and Questionnaires
D000395:Air Pollutants, Occupational; D003077:Coke; D018377:Neurotransmitter Agents; D011084:Polycyclic Aromatic Hydrocarbons; D011721:Pyrenes; D001564:Benzo(a)pyrene; C033146:1-hydroxypyrene