Early life exposure to F-53B induces neurobehavioral changes in developing children and disturbs dopamine-dependent synaptic signaling in weaning mice

Previous studies have shown that F-53B exposure may be neurotoxic to animals, but there is a lack of epidemiological evidence, and its mechanism needs further investigation. Serum F-53B concentrations and Wisconsin Card Sorting Test (WCST) were evaluated in 314 growing children from Guangzhou, China, and the association between them were analyzed. To study the developmental neurotoxicity of F-53B, experiments on sucking mice exposed via placental transfer and breast milk was performed. Maternal mice were orally exposed to 4, 40, and 400 μg/L of F-53B from postnatal day 0 (GD0) to postnatal day 21 (PND 21). Several genes and proteins related to neurodevelopment, dopamine anabolism, and synaptic plasticity were examined by qPCR and western blot, respectively, while dopamine contents were detected by ELISA kit in weaning mice. The result showed that F-53B was positively associated with poor WCST performance. For example, with an interquartile range increase in F-53B, the change with 95% confidence interval (CI) of correct response (CR), and non-perseverative errors (NPE) was -2.47 (95% CI: -3.89, -1.05, P=0.001), 2.78 (95% CI: 0.79, 4.76, P=0.007), respectively. Compared with the control group, the highest exposure group of weaning mice had a longer escape latency (35.24s vs. 51.18s, P=0.034) and a lesser distance movement (34.81% vs. 21.02%, P<0.001) in the target quadrant, as observed from morris water maze (MWM) test. The protein expression of brain-derived neurotrophic factor (BDNF) and growth associated protein-43 (GAP-43) levels were decreased, as compared to control (0.367-fold, P<0.001; 0.366-fold, P<0.001; respectively). We also observed the upregulation of dopamine transporter (DAT) (2.940-fold, P<0.001) consistent with the trend of dopamine content (1.313-fold, P<0.001) in the hippocampus. Early life exposure to F-53B is associated with adverse neurobehavioral changes in developing children and weaning mice which may be modulated by dopamine-dependent synaptic plasticity.