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International audience; Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants originating from incomplete combustion processes. Humans are mainly exposed through contaminated food ingestion. PAHs are neurotoxic compounds both for human and rodents, and may be found in placenta, umbilical cord blood and breast milk, suggesting that early exposure may impact developing central nervous system. In a previous study we showed that PAH exposure during both gestation and lactation periods in rats increased anxiety-related behaviours and decreased cerebral metabolism in several key structures linked to the limbic system on male pups at the adult stage. The aim of the present study was to assess the effects of an exclusive gestational PAH exposure on the same aspects of brain functionality. Female rats were exposed through diet to a 16 PAH mixture at doses of 2 mu g/kg/day or 200 mu g/kg/day during gestation. Late neurotoxic effects were evaluated by carrying out behavioural and cognitive tests and histochemical analyses using cytochrome oxidase activity as a cerebral metabolism marker in different brain areas. The results of this study revealed that behaviour and cerebral metabolism on prenatally PAH exposed adult rats was not significantly affected by the exposure to these pollutants. Finally this work highlights that the exposure period to pollutants such as PAHs at very early stages of development play a key role on the neurological impairment induced. (C) 2013 Elsevier Ireland Ltd. All rights reserved.

International audience; Fluorene is a volatile polycyclic aromatic hydrocarbon (PAH) with an airborne concentration ranging a level of 5 ng/m3. Since no data on fluorene neurotoxicity are available, a study on adult rats was conducted in order to evaluate the neurobehavioural effects of a repeated inhalation exposure. For that, male rats (n = 12/group) were exposed nose-only to 1.5 (10_g/m3) or 150 (1mg/m3) ppb of fluorene 6 h/day for 14 consecutive days, while control animals were exposed to a non-contaminated air. At the end of the period of exposure, animals were tested for spontaneous activity in the open-field, for anxiety in the elevated plus maze, for short term memory in the Y maze and for spatial learning in the eight arm maze. After this exposure, no differences were observed in body and brain weights, whereas a significant decrease of the weight of the liver was measured in fluorene-exposed rats compared to controls. In the open-field, a significant increase in the number of crossed cases and the time spent in the central area of the maze was observed in rats exposed to fluorene. For the same animals, in the elevated plus maze, the times spent in the central place and in the closed arm were respectively significantly higher and lower than controls. Taken together, these results are indicative of a reduction of anxiety in rats exposed to fluorene compared to controls. Learning and memory performances remained unaffected. Otherwise, the weight of the surrenal gland, the blood levels of corticosterone and both depression-related behaviour in the forced swimtest indicated that the restraint stress induced by the model of exposure did not contribute to the effects of fluorene. In conclusion, these results are indicative of the neurotoxicity of fluorene and confirm the possible risk induced by an environmental contamination with PAHs.

International audience

International audience; Organic pollutants like PAHs, PCDD/Fs and PCBs can be transferred to the milk of lactating goats after an oral contamination. This study focused on the effects of an oral chronic administration of milk issued from these goats on brain metabolism and behaviour in adult rats. Four groups of rats (n = 12) were treated with methylcellulose 0.3% (MC), non-contaminated milk (NCGM), contaminated milk with PAHs or with a PCDD/F-PCB mixture (PCM). MC or milk were daily administrated during 3 weeks (0.5 ml/100 g bw, p.o.). At the end of the treatment, rats were studied for their locomotor, spatial memory and anxiety performances in an open-field, a T maze and an elevated plus maze (EPM), respectively. Thus, the animals were sacrificed, the brain removed and the tissue analyzed for fingerprinting using the 1H NMR spectroscopy. Urine samples were also collected once a week over the treating period. The multivariate statistical analysis of the 1H NMR spectra of urine discriminated PAH- and PCM-treated animals from controls (MC, NCGM) after 3 weeks of treatment. At the same time, PAH-treated rats exhibited a reduction of the anxiety-related behaviour in the EPM and deficits of spontaneous alternation in the T maze whereas the PCM animals did not. In the brain, PAHs and PCM induced metabolic deviations compared to controls, but these perturbations were different between the two contaminated groups. These results suggest differences in the neurotoxicity of xenobiotics from one group of pollutants to another, and question the toxicity of these compounds through ingestion of contaminated food.