Biological exposure indices of pyrrole adducts in serum and urine for hazard assessment of n-hexane exposure.
BACKGROUND
Pyrrole adducts might be used as a biomarker for monitoring occupational exposure to n-hexane, but the Biological Exposure Indices of pyrrole adducts in serum and urine are still unknown. The current study was designed to investigate the biological exposure limit of pyrrole adducts for hazard assessment of n-hexane.


METHODS
Male Wistar rats were given daily dose of 500, 1000, 1500, 2000, 4000 mg/kg bw n-hexane by gavage for 24 weeks. The levels of pyrrole adducts in serum and urine were determined at 8, 24 hours postdose once a week. The Biological Exposure Indices was evaluated by neurological evaluation and the levels of pyrrole adducts. The difference in pyrrole adducts formation between humans and rats were estimated by using in vitro test.


RESULTS
Dose-dependent effects were observed between the doses of n-hexane and pyrrole adducts in serum and urine, and the levels of pyrrole adduct in serum and urine approached a plateau at week 4. There was a significantly negative correlation between the time to paralysis and the level of pyrrole adducts in serum and urine, while a positive correlation between gait score and levels of pyrrole adducts in serum and urine was observed. In vitro, pyrrole adducts formed in human serum was about two times more than those in rat serum at the same level of 2,5-HD.


CONCLUSIONS
It was concluded that the BEIs of pyrrole adducts in humans were 23.1 ± 5.91 nmol/ml in serum 8 h postdose, 11.7 ± 2.64 nmol/ml in serum 24 h postdose, 253.8 ± 36.3 nmol/ml in urine 8 h postdose and 54.6 ± 15.42 nmol/ml in urine 24 h postdose.
Institute of Toxicology, School of Public Health, Shandong University, Jinan, Shandong Province, China ; Jinan Municipal Center for Disease Control & Prevention, Jinan, Shandong Province, China.
Hongyin
H
Yin
Nutrition Department, Shandong Jiaotong Hospital, Jinan, Shandong Province, China.
Chunling
C
Zhang
Institute of Toxicology, School of Public Health, Shandong University, Jinan, Shandong Province, China.
Ying
Y
Guo
Institute of Toxicology, School of Public Health, Shandong University, Jinan, Shandong Province, China.
Xiaoying
X
Shao
Institute of Toxicology, School of Public Health, Shandong University, Jinan, Shandong Province, China.
Tao
T
Zeng
Institute of Toxicology, School of Public Health, Shandong University, Jinan, Shandong Province, China.
Xiulan
X
Zhao
Institute of Toxicology, School of Public Health, Shandong University, Jinan, Shandong Province, China.
Keqin
K
Xie
D000328:Adult; D000818:Animals; D015415:Biomarkers / Q000097:blood / Q000652:urine; D001835:Body Weight / Q000187:drug effects; D005260:Female; D005684:Gait / Q000187:drug effects; D006586:Hexanes / Q000008:administration & dosage / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D010243:Paralysis / Q000209:etiology; D017729:Presynaptic Terminals / Q000187:drug effects; D011758:Pyrroles / Q000097:blood* / Q000737:chemistry / Q000652:urine*; D051381:Rats; D013997:Time Factors; D055815:Young Adult
D015415:Biomarkers; D006586:Hexanes; D011758:Pyrroles; C026385:n-hexane