Abstracts / Toxicology Letters 211S (2012) S43–S216 S165 ization, embedded in paraffin cardiac tissue samples, and examined under light microscopy. Telomerase activity in peripheral blood mononuclear cells (PBMC) and on cardiac tissues was measured using a commercial telomerase PCR-ELISA, based on the telom- eric repeat amplification protocol. Oxidative stress indices (reduced glutathione – GSH and thiobarbituric-acid reactive substances – TBARS) were measured in peripheral blood. Results and conclusions: Chloropyrifos administration was associated with a reduction of left ventricular myocardial walls and chamber size, and reduced left ventricular myocardial mass assessed by echocardiography on sedated exposed animals compared to controls. For chloropyrifos- exposed animals no hemorrhagic impregnation, nor signs of inflammation was observed in the cardiac tissue. Telomerase activ- ity both of the cardiac tissue and in PBMCs remained statistically unchanged compared to controls but a profound increase of 300% of GSH and a mild rise of 10% of TBARS was observed. Accumulation of systemic oxidative stress is evident for chlorpyrifos-treated rab- bits after long-term exposure, while a localised cardiotoxic effect has not yet been identified. doi:10.1016/j.toxlet.2012.03.597 P26-10 Electromagnetic treatment of cigarettes and biomarkers of oxidative stress in rats Predrag Vukomanovic 1 , Vesna Matovic 2 , Zoran Radosavljevic 3 , Natasa Radosavljevic 4 , Aleksandra Buha 2 , Milan Jokanovic 5 1 Leko-vita, Pharmacy, Serbia, 2 Faculty of Pharmacy, Serbia, 3 Urology, Internal Hospital, Serbia, 4 Institute of Rehabilitation, Serbia, 5 Faculty of Medicine, Serbia The aim of this work was to investigate the toxic effects of tobacco smoke of cigarettes previously exposed to pulsed electro- magnetic field. For this purpose standard cigarettes were exposed to pulsed electromagnetic irradiation of low power (>10–7 W) and wide fre- quency spectrum (30 Hz to 300 GHz) during 24 h by a patented technology. Experiment was performed on rats of both sexes subjected to tobacco smoke obtained from 16 or 32 cigarettes non- treated or treated with pulsed electromagnetic radiation per day, during 90 days. To assess the toxic effects the following biomark- ers of oxidative stress were measured in erythrocytes of rats: superoxide dismutase and glutathione peroxydase activity, and malondialdehyde concentration. Exposure to tobacco smoke of standard cigarettes induced sig- nificant and dose dependent reduction of enzymes activity and increase of malondialdehyde concentration in rats. On the other hand, electromagnetic treatment succeeded to reduce these effects of tobacco smoke. The activity of both enzymes was elevated and concentration of malondialdehyde was reduced if compared to the levels obtained for rats exposed to non-treated cigarettes. More- over, no significant alterations in the activity of enzymes and malondialdehyde concentration were observed in rats exposed to treated cigarettes if compared to controls. The results of this study show beneficial effect of treatment of cigarettes with pulsed electromagnetic radiation on investigated parameters of oxidative stress. doi:10.1016/j.toxlet.2012.03.598 P26-11 Effects of lycopene and silymarin on antioxidant status in rat liver Gözde Girgin 1 , Terken Baydar 2 , Aysun Kilic 2 , Güldeniz Selmanoglu 2 , Gönül Sahin 2 1 Hacettepe University, Faculty of Pharmacy, Turkey, 2 Hacettepe University, Turkey Lycopene and silymarin are both well-known compounds of herbal origin having antioxidant and protective effects. There are many reports on health benefits of both compounds which are attributed to their ability to protect cells against oxidative damage. The present study was undertaken to evaluate effects of lycopene and silymarin on hepatic oxidant and antioxidant processes in rats. Fifteen female Wistar rats were divided into 3 groups and the treatments were applied for 7 days. Group I was used as a control group and treated with corn oil while Groups II and III were treated with 100 mg/kg lycopene or silymarin, respectively. Liver catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA) and serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (AP), cholesterol and urea levels were investigated. Both of the antioxidants increased liver function enzymes AST and ALT compared to control (p < 0.05, all). Silymarin treatment resulted in significant decrease in CAT and cholesterol and increase in SOD activities while lycopene caused significant increase in AP levels and decrease in urea levels in comparison with the control (p < 0.05, all). There were significant differences in cholesterol, AST and AP levels between lycopene and silymarin groups (p < 0.05, all). Our results indicate that these compounds need to be investigated extensively for both their beneficial and untoward effects. Further studies are needed to evaluate the effects of lycopene and sily- marin on oxidative stress and liver functions at various doses and treatment duration. doi:10.1016/j.toxlet.2012.03.599 P26-12 The role of glutathione reductase in paraquat neurotoxicity Mirjana Djukic 1 , Marina Jovanovic 2 , Milica Ninkovic 2 , Ivana Stevanovic 2 1 Faculty of Pharmacy, Serbia, 2 Military Medical Academy, Serbia Paraquat (PQ), a contact herbicide and environmental pollutant, exerts its toxicity through the production of free radicals, and con- sequently, development of oxidative stress (OS). The goal of our study was to examine if pretreatment with GR could prevent PQ-induced brain injury in Wistar rats. Testing substances in volumes of 10 L were administered intrastriatally (i.s.) by a stereotaxic instrument. Wistar rats were divided into GR, PQ, GR + PQ groups, and two controls: intact and sham-operated. Following parameters of OS and antioxidative response were measured in the vulnerable brain regions (VBRs) (striatum, hip- pocampus and cortex) 30 min, 24 h and 7 days after the treatments: superoxide anion radical (O 2 •- ), nitrate (NO 3 - ) – a final metabolite of nitrogen oxide radicals metabolism, thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD), glutathione per- oxidase (GPx) and glutathione (GSH). In the PQ group, extremely high GPx activity measured at 30 min after the treatment was followed by significant decrease of GPx and SOD activities, GSH depletion and low contents of O 2 •- , NO 3 - and