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168 Abstracts / Toxicology L

Purpose: to investigate aspects of the oxidative stress in rheuma-oid arthritis (RA) patients and to correlate them the disease activitynd the treatment. Methods: the trials has included 43 RA patientsiagnosed according to revised ACR criteria, 1987 (age: 46.4 ± 24.3ears; disease duration: 48.7 ± 38.6 months; 86.6% women), withctive disease (DAS28 > 5.1). Patients clinical response has beenssessed according to EULAR criteria. First group was treated withethotrexate (MTX) in increased doses (up to 20 mg/week) and

nfliximab, the second with MTX and etanercept, the third withTX and rituximab. The oxidative status was evaluated using

AS (Total Antioxidant Status) kit. Samples of serum were keptt −20 ◦C. Patients have been investigated prior to the change ofherapy and subsequently after 6 weeks, 6 months and 1 year.esults and conclusions: The initial TAS mean value of all groupsas 1.58 ± 0.52 mmol/l, 2.21 ± 0.98 mmol/l, 1.58 ± 0.56 mmol/l, atmonths the TAS mean value was higher 2.36 ± 1.20 mmol/l,

.08 ± 0.84 mmol/l, 2.69 ± 1.02 mmol/l, and after 1 year of treat-ent, the TAS value in patients treated with MTX and rituximabas 1.17 ± 0.42 mmol/l.

Our results show that at 6 weeks all three groups had an increasef the antioxidant activity, the interval between 6 weeks and 6onths revealed a decrease of the TAS status in all kinds of treat-ents and from 6 month to 1 year, only the treatment with MTX

nd rituximab showed a decrease of the antioxidant defense. Theesults involve, in fact, the decrease of the activity of the disease,hen patients are treated with MTX and rituximab.

oi:10.1016/j.toxlet.2012.03.607

26-20ubstituted hexahydropyridoindoles—Effective scavengers ofree radicals

ilan Stefek 1, Gregorz Bartosz 2, Maria Juskova 1, Ivanailackova 1, Mojmir Mach 1

Inst Exp Pharmacol Toxicol SAS, Slovakia, 2 University of Lodz,oland

Purpose: The antioxidant activity of the hexahydropyridoin-ole stobadine was well demonstrated in numerous in vitrond in vivo studies (Juranek et al., 2010). Recently, chemicalodification of stobadine led to derivatives with significantly

ncreased antiradical activity. The objective of the present studyas evaluation of the antioxidant action of SMe1EC2, the 8-ethoxy analogue of stobadine with acyl substituent at the

ynthetically accessible position N2 devoid of the unwantedlpha-adrenolytic action. Results: The intrinsic antiradical activ-ty of SMe1EC2 was found significantly higher when comparedo stobadine as determined in cell-free model systems including1,1TM-diphenyl-2-picrylhydrazyl scavenging and 2,2′-azobis(2-

midinopropane) hydrochloride (AAPH)-induced oxidation of twouorogenic probes. When erythrocytes were used as a cellu-

ar model, stobadine more efficiently protected the cells againstemolysis induced by hydrophilic AAPH. On the other hand,Me1EC2 did exceed stobadine in its antioxidant action whenipophilic t-BuOOH was used to initiate the hemolysis. To accountor the apparent discrepancy, the variance of basicity of SMe1EC2s. stobadine, affecting the mutual location of the antioxidantnd radicals, was taken into consideration. In compliance withhe above mentioned findings, SMe1EC2 was found more effec-

ive in scavenging reactive oxygen/nitrogen species in stimulated

acrophage RAW 264.7 cell cultures. In addition, studies in pri-ary human umbilical vein endothelial cell lines revealed that both

Me1EC2 and stobadine did not decrease significantly the viability

211S (2012) S43–S216

of the cells. Both compounds demonstrated neither embryotoxicnor teratogenic effects on rat fetuses and no signs of maternal tox-icity were found. Conclusion: The hexahydropyridoindole skeletonof stobadine represents an interesting scaffold. Its modificationmay yield congeners tailored according to specific requirementsfor antiradical efficacy, lipophilicity and basicity, meeting the aimof providing a pharmacologically practicable antioxidant drug.

Reference

Juranek, I., et al., 2010. Curr. Med. Chem. 17 (6), 552–570.

doi:10.1016/j.toxlet.2012.03.608

P26-21KBrO3 induces oxidative stress and tight junction alterationsin proximal tubule cells

Alice Limonciel 1, Anja Wilmes 1, Lydia Aschauer 1, RobertRadford 2, Katarzyna Bloch 3, Craig Slattery 2, Edward Lock 3,Michael P. Ryan 2, Paul Jennings 1

1 Innsbruck Medical University, Austria, 2 University College Dublin,Ireland, 3 Liverpool John Moores University, United Kingdom

Purpose: Potassium bromate (KBrO3) is an oxidising agentnotably used in the food industry as a maturing agent for flour.It has shown to be both a nephrotoxin and a renal carcino-gen in several in vivo and in vitro models. Here we investigatedthe effects of KBrO3 in the human and rat proximal tubular celllines RPTEC/TERT1 and NRK-52E. Methods and results: A genome-wide transcriptomic screen was carried out after treatment witha sub-cytotoxic concentration of KBrO3 for 6, 24, and 72 h. Path-way analysis of altered gene expressions identified Glutathionemetabolism, Nrf2-mediated oxidative stress and Tight junction(TJ) signaling as among the most enriched pathways. The latterpathway was less impacted in NRK-52E cells due to the absenceof several TJ proteins in addition to a lack of barrier function inthese cells. In RPTEC/TERT1 cells, KBrO3 exposure caused a decreasein trans-epithelial electrical resistance (TEER) and altered theexpression of several TJ proteins. Co-incubation with antioxidant N-acetylcystein (NAC) prevented activation of the Nrf2 downstreamprotein NQO1, as well as the TEER decrease and the KBrO3-inducedalterations of the tight junction proteins. Conclusions: These resultsdemonstrate the effect of oxidative stress and its activation of thecytoprotective Nrf2 pathway on the expression and function oftight junction proteins. The further understanding of the interac-tion between these two pathways could have major implicationsfor epithelial repair, carcinogenesis and metastasis.

doi:10.1016/j.toxlet.2012.03.609

P26-22NAC prevents high-P/Zn-free diet-induced peripheral nervousdysfunction

Sahoko Ichihara 1, Yuka Suzuki 1, Ai Kato 1, Takahiro Yamaguchi 1,Gaku Ichihara 2

1 Mie University, Japan, 2 Nagoya University Graduate School of Med,Japan

Purpose: It is known that the patients with type 2 diabetesmellitus affect peripheral nervous system. However, it is unclearwhether metabolic syndrome is associated with peripheral neu-