Validation of Armadillo officinalis Dumèril, 1816 (Crustacea, Isopoda, Oniscidea) as a bioindicator: In vivo study of air benzene exposure

• This study tests Armadillo officinalis as bioindicator of exposure to benzene.
• Benzene was detected in exoskeleton of A. officinalis by GC–MS.
• Muconic acid was detected in hepatopancreas and other tissue of A. officinalis.
• S-phenylmercapturic acid was detected in hepatopancreas and other tissue of A. officinalis.
• mtDNA copy number increase was related to rising benzene doses.
• For first time our findings showed that A. officinalis reproduce human metabolism.

This study tests the potential for using Armadillo officinalis as a bioindicator of exposure to and activation of benzene metabolic pathways using an in vivo model.A. officinalis specimens collected in a natural reserve were divided into a control and three test groups exposed to 2.00, 5.32 or 9.09 µg/m3 benzene for 24 h. Three independent tests were performed to assess model reproducibility. Animals were dissected to obtain three pooled tissue samples per group: hepatopancreas (HEP), other organs and tissues (OOT), and exoskeleton (EXO). Muconic acid (MA), S-phenylmercapturic acid (S-PMA), two human metabolites of benzene, and changes in mtDNA copy number, a human biomarker of benzene exposure, were determined in each sample; benzene was determined only in EXO. MA was measured by high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection, S-PMA by triple quadrupole mass spectrometer liquid chromatography with electro spray ionization (LC-MS-ESI-TQD), mtDNA by real-time quantitative PCR and end-point PCR, and benzene by quadrupole mass spectrometer head-space gas chromatography (HSGC-MS).MA and S-PMA levels rose both in HEP and OOT; EXO exhibited increasing benzene concentrations; and mtDNA copy number rose in HEP but not in OOT samples. Overall, our findings demonstrate that A. officinalis is a sensitive bioindicator of air benzene exposure and show for the first time its ability to reproduce human metabolic dynamics.