Neurobehavioural toxicity of A 14-day exposure to the airborne polycyclic aromatic hydrocarbon fluorene in adult wistar male rats

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English. 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.