The correlation between nonylphenol concentration in brain regions and resulting behavioral impairments

Nonylphenol (NP) has been introduced as the most common endocrine disturbing-chemical (EDC) in the environment. NP exerts several adverse effects on the reproductive system, immune system, and central nervous system (CNS) via its potent hormonal activity. In this study, the correlation between NP concentration and the resulting memory impairment and induction of anxiety was examined in adult rats. NP (at doses of 0.2 or 2 mg/kg) and corn oil (as NP vehicle) were orally administrated for 35 days. On day 36, animals were evaluated for anxiety and cognitive performance using elevated plus maze and Morris water maze test, respectively. Rats were sacrificed afterwards for serum, cerebrospinal fluid (CSF), amygdala, and hippocampus NP level measurement using high performance liquid chromatography (HPLC). The behavioral results indicated that NP exposure at the dose of 2 mg/kg significantly reduces spatial learning and memory. Additionally, anxiety-like behavior was increased in animals received NP exposure compared to the vehicle group. Analysis of HPLC results showed that high quantity of NP is accumulated in hippocampus and amygdala tissues. Regression analysis showed a significant linear correlation between NP concentration and behavioral impairment. Overall, these data demonstrate the significant relationship between NP concentration in particular brain regions and the behavioral deficit.