Cumulative low doses of the organic pesticide rotenone in the adult rat substantia nigra pars compacta. Rattus norvegicus

Adult male Sprague Dawley rats (5 month-old at the beginning of the study) were subcutaneously exposed to 0.5 mg.kg/d rotenone or the corresponding solvent (PEG/DMSO, 1/1) for 28 days. At the end of the experiment, animals were sacrificed by decapitation and brains were rapidly taken out within 30-40 s. Total RNA was prepared from laser-capture microdissected rat substantia nigra pars compacta (Snpc). Changes in transcript abundance within SNpc were analyzed on samples from solvent and rotenone-exposed groups (n = 3 per group) using CodeLink™ Rat Whole Genome bioarrays containing 34,000 transcripts and EST probes (GE Healthcare, Amersham, Saclay, France). Overall design: Two groups of rats were exposed either to rotenone (CR rats) or to solvents (CS rats) in order to analyse pesticides impact on gene expression.