Abstracts / Toxicology Letters 221S (2013) S59–S256 S145

Subchronic PQ exposures were done over 10 days at bothstages. Thereafter, general adverse effects and neuroinflamma-tory responses were assessed by measuring changes in gene- andprotein expression as well as by determining changes in cell mor-phology.

Nano-molar PQ-concentration had no effect on mature cultures,however undifferentiated cultures displayed a 50% decrease in neu-ronal marker expression, accompanied by a strong astrogliosis. Inmature cultures similar loss of neuronal markers could only beobserved with a 10-fold higher PQ dose, and – contrary to undiffer-entiated cultures – did not correlate with an increase in astroglialreactivity.

These results show that developing brain cells respond differ-ently to chemical insult of paraquat compared to mature braintissue. The strong response of neural cultures undergoing differ-entiation also supports the hypothesis of increase susceptibilityduring certain stages of development.

http://dx.doi.org/10.1016/j.toxlet.2013.05.290

P12-24Effects of culture on polymer biomaterials onthe cellular responses to chemicals

Atsuko Miyajima-Tabata ∗, Reiko Kato, Keiko Sakai, AtsukoMatsuoka

National Institute of Health Sciences, Tokyo, Japan

Purpose: Synthetic polymer materials have been developed andapplied to medical devices. 2-Methacryloyloxyethyl phosphoryl-choline polymer (MPC polymer) shows good biocompatibility, withreduced protein adsorption, and is used as a surface ornamen-tation agent with artificial organs, blood-contact medical tubing,catheters and contact lenses. In this study, the cellular responses tocytotoxic chemicals were evaluated in three cell lines cultured onplates using MPC polymers as the substrate. Methods: Chinese ham-ster lung fibroblasts (CHL), human lung epithelial-like cells (A549)and mouse macrophage-derived cells (RAW264.7) were culturedon MPC or control plates, and the cell proliferation and cytotoxicityin response to treatment with chemicals were examined. A geno-toxicity test was carried out using the micronucleus test in CHL andA549 cells. Results and conclusions: On MPC plates, CHL cells gath-ered into clusters of tens to hundreds of cells and formed spheroids.In contrast, A549 and RAW cells grew in grape-like bunches. Thedoubling times of CHL and RAW cells were almost the same for bothtypes of plates, but the doubling time of A549 cells was about fourtimes longer on MPC plate than on the control plate. No remark-able differences were observed in the genotoxicity test results ineither CHL or A549 cells. However, it was found that the three celllines showed different sensitivities to CdSO4 and ZnO when theywere cultured on MPC plates. A further analysis of the relationshipbetween the cell morphology and the response to chemicals wouldhelp provide a better understanding of the mechanisms underlyingbiocompatibility.

http://dx.doi.org/10.1016/j.toxlet.2013.05.291

P12-25Effects of extended low-load operation of anon-DPF diesel engine on the relative toxicity ofits emissions

Jan Topinka 1,∗, Pavel Rossner 1, Alena Milcova 1, JanaSchmuczerova 1, Andrea Rossnerova 1, Jitka Pavlikova 1, AntoninAmbroz 1, Zuzana Novakova 1, Vlasta Svecova 1, MichalVojtisek-Lom 2

1 Institute of Experimental Medicine AS CR, Prague 4, Czech Republic,2 Technical University of Liberec, Liberec, Czech Republic

The study was performed to identify possible genotoxicityinduced by organic extracts from particulate matter in the exhaustof diesel engine Zetor 1505 running on diesel and biodiesel (B100)fuels at various operating conditions typical for transit truck traf-fic in large cities. Diluted exhaust was sampled with high-volumesamplers on Teflon coated filters. Filters were extracted withdichlormethane and DNA adduct levels and DNA oxidative damage(8-oxo-dG) induced by extractable organic matter in an acellularassay of calf thymus DNA coupled with 32P-postlabeling in thepresence and absence of rat liver microsomal S9 fraction wereemployed. Moreover, model of human lung epithelial cells (A549)was used to study cytotoxicity, genotoxicity (DNA adducts andmicronuclei) and oxidative damage of lipids and proteins. Theresults suggest highest adduct levels for high load immediatelyfollowing a period of extended low-load operation on diesel fuel(1.63 adducts/108 nucleotides), 3-fold higher than for biodieselB100 (0.54 adducts/108 nucleotides). The results of oxidative dam-age of biomolecules and micronucleus test did not indicate cleartoxic effects of EOMs and will be further investigated. The data indi-cate relatively high genotoxicity of exhaust produced during highload immediately following a period of extended low-load opera-tion operating condition, compared to other operating conditions,for both fuels in an acellular assay as well as in human lung cellline. Under this operating condition, diesel fuel emissions exhibitapproximately 3-fold higher genotoxicity compared to biodieselB100.

Support: EU LIFE+ project MEDETOX (LIFE10 ENV/CZ/651) andCzech Science Foundation Grant 13-01438S.

http://dx.doi.org/10.1016/j.toxlet.2013.05.292

P12-26Effects of neurotoxic compounds on functionalthree-dimensional neural tissues derived fromhESCs

L. Stoppini 1,3,∗, I. Charvet 1,2, K.H. Krause 2

1 Hepia, HESSO Geneva, Switzerland, 2 University of Geneva,Switzerland, 3 SCAHT, Switzerland

Purpose: Human embryonic stem cells (ESCs) are potentialsource of human neurons that can serve to develop in vitro engi-neering tissue aimed to fundamental research. Three dimensional(3D) tissue engineering designs a complex biological structurebridging the gap between classical 2D cell culture and animal tissue.The aim of our work is to develop 3D stable and long term in vitroculture conditions that may help to model in vitro neurotoxicity.Methods: hESCs H9-derived NSC were maintained in proliferat-ing state through culture on laminin in presence of growth factorsEGF and bFGF. Neuronal and glial differentiation were induced byomitting growth factors and by plating high density of NSC ontoporous membrane (air–liquid interface culture system) to generate