- Email: [email protected]
Synthesis and characterization of biomarkers of exposure to 1-bromopropane
S80
Abstracts / Toxicology Letters 258S (2016) S62–S324
gene fragmentation and deletion were assessed by comet-FISH technique. No increase in tail length or tail intensity compared to control (13.8 ± 1.19 m and 0.09 ± 0.20% of DNA, respectively) was observed; only for 3 g/ml of imidacloprid tail length significantly increased (14.5 ± 1.06 m). Concerning TP53 structural integrity, no significant increase in rate of gene fragmentation or deletion was detected compared to control (6.7% and 3.3%, respectively). Statistically insignificant increase in TP53 migration in the comet tail was spotted at 3 g/ml of ␣-cypermethrin (16.7%) and imidacloprid (13.3%). Insignificant increase in TP53 deletion rate was observed for ␣-cypermethrin at 3 g/ml (10.0%) compared to control (3.3%). Observed effects on level of primary DNA damage and TP53 structural integrity and copy number could not be considered biologically significant. At the low concentrations in extended term exposure applied in the study all three insecticides may be considered safe. This work was supported by Croatian Science Foundation under the project 8366. http://dx.doi.org/10.1016/j.toxlet.2016.06.1366 P02-009 “In vivo” model for predicting organophosphate toxicity using humanized-liver chimeric mouse H. Suemizu 1,∗ , M. Kuronuma 1 , K. Kawai 1 , N. Murayama 3 , M. Nakamura 2 , H. Yamazaki 3 1 Laboratory Animal Research Department, Central Institute for Experimental Animals, Kanagawa, Japan 2 Department of Pathology and Regenerative Medicine, Tokai University, Kanagawa, Japan 3 Laboratory of Drug Metabolism and Pharmacokinetics, Showa Pharmaceutical University, Tokyo, Japan
The diagnostic procedure for acute organophosphorus pesticide (OP) toxicity in humans involves the definitive measurement of plasma butyrylcholinesterase (BuChE) activity. However, it is well known that the plasma BuChE activity differ between human and mice. In the humanized-liver (Hu-liver) TK-NOG mouse model, the liver is replaced with transplanted human hepatocytes and therefore, produces human hepatic proteins including drug metabolizing enzymes and secretory proteins. The plasma BuChE activity of Hu-liver TK-NOG mice was incomparably higher than that of non-humanized TK-NOG mice (258 ± 127 and 28 ± 10 IU/L, n = 309 and 36, respectively), but comparable to that in humans. In this study, we evaluated plasma BuChE activity in Hu-liver TK-NOG mice to determine if it could serve as a predictive marker for OP toxicity. Single oral administration of non-lethal doses of acephate and chlorpyrifos (300 and 10 mg/kg, respectively) to Hu-liver TKNOG mice almost completely abolished the plasma BuChE activity at 7 and 0.5 h, respectively. A dose-dependent decrease in plasma BuChE activity was observed at the most effective doses of acephate and chlorpyrifos, which ranged from 1 to 300, and 0.1 to 3 mg/kg, respectively. Nevertheless, the dose of chlorpyrifos (3 mg/kg) that induced no clinical signs of overt toxicity significantly reduced both plasma BuChE activity and objective assessment data for motor activity. Therefore, the inhibition of plasma BuChE is not an adverse effect itself but may indicate a potential for the induction of adverse effects by OP toxicity in experimental animal models. http://dx.doi.org/10.1016/j.toxlet.2016.06.1367
P02-010 Synthesis and characterization of biomarkers of exposure to 1-bromopropane R.F. Gomes, J. Nunes, M. Marques ∗ Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Portugal 1-Bromopropane (BP) is a brominated hydrocarbon used as solvent in many industrial and commercial applications. Occupational exposure (up to 380 ppm) (Anon, 2011), through inhalation and dermal contact, has increased in recent years due to BP use as a replacement for suspected carcinogens and ozone-depleting chemicals. BP was recently classified by the International Agency for Research on Cancer (IARC) as ‘possibly carcinogenic to humans’ (Group 2B) based on ‘sufficient evidence’ of carcinogenicity in experimental animals (Grosse et al., 2016). Studies in humans and laboratory animals indicate that BP can be absorbed upon inhalation, ingestion, or dermal exposure. Urinary mercapturates were detected in humans and animal models, and cytochrome P450 2E1-mediated metabolism was identified in rodents (Anon, 2011). However, data on DNA and protein adducts potentially involved in BP-induced toxicity and carcinogenicity are scarce. In this work we synthesized and characterized (NMR and LC/ESIMS) a series of covalent amino acid- and deoxynucleoside adducts by direct reaction with BP. Likewise, BP reacted with DNA, primarily leading to depurination. Extensive reaction also occurred with human serum albumin, where over 25 sites of adduction (mostly lysines and histidines) were identified by bottom-up proteomics. These results suggest that BP exposure may pose a significant risk of toxicity and call for further evaluation in vivo. Acknowledgements: Fundac¸ão para a Ciência e a Tecnologia (FCT, Portugal) for financial support (RECI/QEQ-MED/0330/2012, UID/QUI/00100/2013, and a doctoral fellowship to RFAG) and the Portuguese MS network (IST node). References 2011. Natl. Toxicol. Prog. Tech. Rep. Ser. 564, 1–190. Grosse, Y., et al., 2016. Lancet Oncol. 17, 419–420.
http://dx.doi.org/10.1016/j.toxlet.2016.06.1368
Abstracts / Toxicology Letters 258S (2016) S62–S324
gene fragmentation and deletion were assessed by comet-FISH technique. No increase in tail length or tail intensity compared to control (13.8 ± 1.19 m and 0.09 ± 0.20% of DNA, respectively) was observed; only for 3 g/ml of imidacloprid tail length significantly increased (14.5 ± 1.06 m). Concerning TP53 structural integrity, no significant increase in rate of gene fragmentation or deletion was detected compared to control (6.7% and 3.3%, respectively). Statistically insignificant increase in TP53 migration in the comet tail was spotted at 3 g/ml of ␣-cypermethrin (16.7%) and imidacloprid (13.3%). Insignificant increase in TP53 deletion rate was observed for ␣-cypermethrin at 3 g/ml (10.0%) compared to control (3.3%). Observed effects on level of primary DNA damage and TP53 structural integrity and copy number could not be considered biologically significant. At the low concentrations in extended term exposure applied in the study all three insecticides may be considered safe. This work was supported by Croatian Science Foundation under the project 8366. http://dx.doi.org/10.1016/j.toxlet.2016.06.1366 P02-009 “In vivo” model for predicting organophosphate toxicity using humanized-liver chimeric mouse H. Suemizu 1,∗ , M. Kuronuma 1 , K. Kawai 1 , N. Murayama 3 , M. Nakamura 2 , H. Yamazaki 3 1 Laboratory Animal Research Department, Central Institute for Experimental Animals, Kanagawa, Japan 2 Department of Pathology and Regenerative Medicine, Tokai University, Kanagawa, Japan 3 Laboratory of Drug Metabolism and Pharmacokinetics, Showa Pharmaceutical University, Tokyo, Japan
The diagnostic procedure for acute organophosphorus pesticide (OP) toxicity in humans involves the definitive measurement of plasma butyrylcholinesterase (BuChE) activity. However, it is well known that the plasma BuChE activity differ between human and mice. In the humanized-liver (Hu-liver) TK-NOG mouse model, the liver is replaced with transplanted human hepatocytes and therefore, produces human hepatic proteins including drug metabolizing enzymes and secretory proteins. The plasma BuChE activity of Hu-liver TK-NOG mice was incomparably higher than that of non-humanized TK-NOG mice (258 ± 127 and 28 ± 10 IU/L, n = 309 and 36, respectively), but comparable to that in humans. In this study, we evaluated plasma BuChE activity in Hu-liver TK-NOG mice to determine if it could serve as a predictive marker for OP toxicity. Single oral administration of non-lethal doses of acephate and chlorpyrifos (300 and 10 mg/kg, respectively) to Hu-liver TKNOG mice almost completely abolished the plasma BuChE activity at 7 and 0.5 h, respectively. A dose-dependent decrease in plasma BuChE activity was observed at the most effective doses of acephate and chlorpyrifos, which ranged from 1 to 300, and 0.1 to 3 mg/kg, respectively. Nevertheless, the dose of chlorpyrifos (3 mg/kg) that induced no clinical signs of overt toxicity significantly reduced both plasma BuChE activity and objective assessment data for motor activity. Therefore, the inhibition of plasma BuChE is not an adverse effect itself but may indicate a potential for the induction of adverse effects by OP toxicity in experimental animal models. http://dx.doi.org/10.1016/j.toxlet.2016.06.1367
P02-010 Synthesis and characterization of biomarkers of exposure to 1-bromopropane R.F. Gomes, J. Nunes, M. Marques ∗ Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Portugal 1-Bromopropane (BP) is a brominated hydrocarbon used as solvent in many industrial and commercial applications. Occupational exposure (up to 380 ppm) (Anon, 2011), through inhalation and dermal contact, has increased in recent years due to BP use as a replacement for suspected carcinogens and ozone-depleting chemicals. BP was recently classified by the International Agency for Research on Cancer (IARC) as ‘possibly carcinogenic to humans’ (Group 2B) based on ‘sufficient evidence’ of carcinogenicity in experimental animals (Grosse et al., 2016). Studies in humans and laboratory animals indicate that BP can be absorbed upon inhalation, ingestion, or dermal exposure. Urinary mercapturates were detected in humans and animal models, and cytochrome P450 2E1-mediated metabolism was identified in rodents (Anon, 2011). However, data on DNA and protein adducts potentially involved in BP-induced toxicity and carcinogenicity are scarce. In this work we synthesized and characterized (NMR and LC/ESIMS) a series of covalent amino acid- and deoxynucleoside adducts by direct reaction with BP. Likewise, BP reacted with DNA, primarily leading to depurination. Extensive reaction also occurred with human serum albumin, where over 25 sites of adduction (mostly lysines and histidines) were identified by bottom-up proteomics. These results suggest that BP exposure may pose a significant risk of toxicity and call for further evaluation in vivo. Acknowledgements: Fundac¸ão para a Ciência e a Tecnologia (FCT, Portugal) for financial support (RECI/QEQ-MED/0330/2012, UID/QUI/00100/2013, and a doctoral fellowship to RFAG) and the Portuguese MS network (IST node). References 2011. Natl. Toxicol. Prog. Tech. Rep. Ser. 564, 1–190. Grosse, Y., et al., 2016. Lancet Oncol. 17, 419–420.
http://dx.doi.org/10.1016/j.toxlet.2016.06.1368