The impact of sodium nitrite and intermittent fasting on neurofilament and tau protein phosphorylation, and spatial learning in rat hippocampus.

In recent years, the influence of dietary-related factors on neurodegenerative diseases has received considerable attention in the academic community, notably involving the food additive sodium nitrite (NaNO₂) and intermittent fasting behavior. However, the effects of NaNO₂ and intermittent fasting on spatial learning and memory have not been thoroughly investigated. This study conducted a controlled experiment to explore the impact of NaNO₂ and intermittent fasting on the hyperphosphorylation of hippocampal neurofilament (NF) and tau proteins, as well as spatial learning and memory in rats. Through Morris water maze experiments, the spatial learning and memory abilities of rats were assessed, while immunoblotting and immunohistochemistry techniques were employed to evaluate the phosphorylation levels and distribution of NF and tau proteins in the rat hippocampus. NaNO₂ was found to induce hyperphosphorylation of hippocampal NF and tau proteins at the Ser396/404 sites, which was accompanied by a decline in spatial learning and memory abilities. Conversely, intermittent fasting ameliorated the NaNO₂-induced hyperphosphorylation of hippocampal neurofilaments and the decline in learning and memory abilities, with no discernible effect on hippocampal tau protein hyperphosphorylation.