Evidence that hydrogen peroxide, a component of oxidative stress, induces high-anxiety-related behaviour in mice

The link between oxidative stress and high-anxiety-related behaviour is uncontested; but the cause-effect relationship has yet to be completely elucidated. Here, the behavioural effects of hydrogen peroxide (H ₂ O ₂ ), given to mice (n = 10 per group) in drinking water at 1%, were assessed in the light/dark choice test, the open field, the elevated-plus maze and the hole-board test. Compared to controls (drinking only water), subacute exposure (10–15 days) of mice to H ₂ O ₂ , the major component of reactive oxygen species (ROS) and the precursor of potent oxidants (hydroxyl radical and hypochlorous acid), affected emotional responses by inducing an anxious behaviour associated with hyperactivity. Our findings clearly showed that H ₂ O ₂ -treated mice exhibited anxiogenic behaviour in the light/dark choice test and in the hole-board test. Moreover, H ₂ O ₂ -treated mice displayed a hyperactive behaviour, revealed by a significant increase in the number of crossings made in the open field test relative to controls. Although H ₂ O ₂ -exposed mice made significantly less head-dippings in the open arms than controls, H ₂ O ₂ -induced hyperactivity may have blurred anxiogenic-like behaviour in H ₂ O ₂ -treated mice in the elevated-plus maze. Our findings provide the evidence that H ₂ O ₂ , an oxidizing component, caused high-anxiety-related behaviour associated with hyperactivity in mice. Antioxidants may play a role in preventing or attenuating oxidative stress-related anxiety.