Early myelin-associated histological and cellular changes after ketogenic diet or ketone ester treatment in a cuprizone/rapamycin mouse model
In a cuprizone/rapamycin‑induced demyelination model, short‑term ketogenic diet (KD) or intermittent ketone‑ester injections (iKE) raised circulating β‑hydroxybutyrate and increased myelin basic protein immunoreactivity during early recovery, without measurable behavioral benefit.
Study and findings
Male C57BL/6 mice were demyelinated with cuprizone and rapamycin for six weeks. After a seven‑day rapamycin washout while cuprizone exposure continued, animals received either a standard diet (SD), a ketogenic diet (KD), or intermittent ketone‑ester injections (iKE) for nine days. Blood β‑hydroxybutyrate (βHB) levels were higher in KD and iKE groups at selected time points compared with SD. Histological analysis showed that both KD and iKE were associated with increased myelin basic protein (MBP) immunoreactivity relative to SD. KD also showed elevated Iba1 immunoreactivity (a microglial marker) and reduced Oil Red O‑positive neutral lipid staining, whereas iKE was linked to higher densities of mature (Olig2⁺CC1⁺) and early‑myelinating (Olig2⁺BCAS1⁺) oligodendrocytes, together with lower plasma TNF‑α and IL‑10. Exploratory behavior did not differ among groups.
Clinical interpretation
The data suggest that metabolic ketosis, whether induced by diet or exogenous ketone esters, can modulate cellular pathways involved in myelin repair in this acute demyelination model. Increased MBP immunoreactivity indicates enhanced myelin protein presence, while the rise in mature oligodendrocyte markers after iKE points to accelerated oligodendrocyte differentiation. The concurrent reduction in pro‑inflammatory cytokines (TNF‑α) and anti‑inflammatory IL‑10 may reflect a shift in the lesion microenvironment that favors remyelination. However, the absence of behavioral improvement over the nine‑day period indicates that histological changes did not translate into functional recovery within this short timeframe.
Limitations and open questions
The study is limited to a single mouse strain and a short recovery window; longer‑term outcomes and translational relevance to human multiple sclerosis remain uncertain. The interventions differed not only in ketone delivery but also in macronutrient composition (KD) versus isolated ketone esters, making it difficult to isolate the effect of ketone availability from dietary factors. Plasma cytokine measurements were limited to TNF‑α and IL‑10, leaving broader inflammatory pathways unexplored. Future work should assess whether sustained ketosis leads to functional improvements, determine the relative contribution of dietary fat versus ketone bodies, and evaluate dose‑response relationships of exogenous ketones in chronic demyelination models.
Source
The findings are drawn from a preclinical mechanistic study (PMID 42887228).