Aggravated behavioral and neurochemical deficits and redox imbalance in mice with enhanced neonatal iron intake: improvement by biochanin A and role of microglial p38 activation.

Objectives: We aim to investigate the joint effect of iron (enhanced neonatal iron intake), 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and biochanin A (BA, oral administration) and possible mechanisms for action on behavioral and neurochemical indicators in the mice. Methods: Rotarod test, pole test and swim test were used to evaluate animal behavior. The neurochemical analysis was conducted by HPLC-ECD. Oxidative stress was determined in this study. Further mechanism was investigated through in vitro experiments. Results: Iron and MPTP co-administration significantly induced behavioral deficits and decreased striatal dopamine content in the male and female mice. The co-administration of iron and MPTP also significantly induced redox imbalance in the substantia nigra (SN) of mice. Furthermore, BA significantly improved behavioral deficits and increased striatal dopamine content in the mice co-treated with iron and MPTP. BA also significantly improved redox imbalance in the SN of mice co-administered with iron and MPTP. Finally, we showed that iron and 1-Methyl-4-phenylpyridinium (MPP ⁺ ) co-treatment significantly increased superoxide production in microglial cultures by inducing p38 mitogen-activated protein kinase (MAPK) activation. BA also significantly decreased superoxide production and p38 MAPK phosphorylation in the cultures co-treated with iron and MPP ⁺ . Conclusion: Iron and MPTP co-treatment may result in worsened behavioral and neurochemical deficits and aggravated redox imbalance through inducing microglial p38 MAPK activation. BA may improve behavioral and neurochemical deficits and redox imbalance through repressing microglial p38 MAPK activation.