New candidate proteins for benzo(a)pyrene-induced spatial learning and memory deficits

Spatial learning and memory (LM) is a property of central importance in the nervous system, yet many of the molecular mechanisms for benzo(a)pyrene[B(a)P]-induced LM deficits remain enshrouded in mystery. In this study, influence of exposure to B(a)P on LM deficits in adult male Sprague-Dawley rats was evaluated by Morris water maze. Then morphological changes in the ultramicrostructure of hippocampal neurons were observed by transmission electron microscopy. Furthermore, to better understand the molecular changes that occur in B(a)P induced LM deficits, antibody-based protein microarrays was used to analyze protein expression changes in rats submitted to sub-chronic oral gavage of B(a)P (2 mg/kg for 90 days). Results suggested that rats in the B(a)P-treated groups have significantly impaired Morris water maze performance when compared to controls. Meanwhile, the B(a)P-induced neuronal damage was also found in the hippocampus under transmission electron microscopy. Our results demonstrate that LM deficits associated protein expression signatures could be identified from tissue proteomes, as well as potential biomarkers such as retinoic acid receptor b (RARb), synaptotagmin iosfomrs 1 (Syt1) and Brain-derived neurotrophic factor (BDNF), previously not found. This study, therefore, identifies, for the first time, multiple novel proteins that are dysregulated by B(a)P, which both enhance our understanding of B(a)P induced LM deficits and represent targets of novel therapeutics.