ORIGINAL PAPER
Hemimellitene (1,2,3-trimethylbenzene) in the liver, lung, kidney, and blood, and dimethylbenzoic acid isomers in the liver, lung, kidney and urine of rats after single and repeated inhalation exposure to hemimellitene
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Nofer Institute of Occupational Medicine, Łódź, Poland
(Department of Toxicology and Carcinogenesis)
Corresponding author
Radosław Świercz
Nofer Institute of Occupational Medicine, Department of Toxicology and Carcinogenesis, św. Teresy 8, 91-348 Łódź, Poland
Int J Occup Med Environ Health. 2016;29(1):113-28
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ABSTRACT
Objectives: The aim of the study has been to explore hemimellitene distribution in blood, liver, lung and kidney as well as
toxicokinetics of its elimination from blood of rats after single and repeated inhalation exposure to this compound. Tissue
distribution and excretion with urine of 2-dimethylbenzoic acids (2,3-DMBA and 2,6-DMBA) were also evaluated. Material and Methods: Male outbred IMP:WIST rats were used in the experiment. The animals were exposed to hemimellitene
vapors at the nominal concentration of 25 ppm, 100 ppm, and 250 ppm in the dynamic inhalation chambers for 6 h
for single exposure purpose and for 4 weeks (6 h/day for 5 day/week) for repeated exposure purposes. Results: Significantly
lower concentrations of hemimellitene were detected in the blood and tissues of animals after repeated inhalation exposure
of animals to hemimellitene vapors, which points to reduced retention of the chemical in the lungs of the experimental rats.
The trend of hemimellitene elimination from the blood depended solely on exposure intensity, irrespective of exposure
time, both after single and repeated exposure. As regards the 2 determined hemimellitene metabolites, the major trend of
the metabolic transformation involved formation of 2,3-DMBA. Conclusions: The significantly higher urinary 2,3-DMBA
concentration after repeated exposure shows that hemimellitene induces enzymatic processes in the rat.