Diffusion MRI reveals stage-dependent microstructural responses to early ferroptosis inhibition in experimental...

Neurodegeneration drives irreversible disability in multiple sclerosis (MS). Ferroptosis has been implicated in MS and experimental autoimmune encephalomyelitis (EAE), but its spatiotemporal dynamics and imaging correlates remain unclear.

We combined 7.0 T diffusion tensor imaging (DTI) with histopathological and molecular analyses to evaluate the effects of Liproxstatin-1 (Lip-1) in mice with EAE induced by myelin oligodendrocyte glycoprotein peptide 35-55 (MOG_35-55). Sixty-four female C57BL/6 mice were assigned to control, EAE, early-treatment (Early-Tx; Lip-1 from day 12), and late-treatment (Late-Tx; Lip-1 from day 18) groups. Magnetic resonance imaging (MRI) and tissue analyses were performed at days 20 and 30 post-immunization.

Early-Tx reduced clinical severity at day 30 (vs. EAE; p < 0.001) and limited body weight loss. At peak disease, voxel- and ROI-based DTI showed increased mean diffusivity and radial diffusivity in the corpus callosum, internal capsule, and thalamus, which were attenuated by Early-Tx. At the chronic stage, EAE showed persistent fractional anisotropy reduction in periventricular white matter and corpus callosum, whereas Early-Tx largely prevented these abnormalities. Histology demonstrated that Early-Tx suppressed inflammatory infiltration, microglial activation, and demyelination while preserving myelin integrity. Acyl-CoA synthetase long-chain family member 4 (ACSL4) upregulation and glutathione peroxidase 4 (GPX4) downregulation preceded overt iron deposition, whereas iron accumulation emerged mainly at the chronic stage and colocalized with activated microglia and demyelinated lesions.

Ferroptosis-related molecular alterations are associated with stage-dependent inflammatory demyelinating injury in EAE. Early Lip-1 treatment provides greater microstructural protection than delayed treatment. High-field DTI sensitively detects treatment-responsive microstructural injury and may help monitor ferroptosis-related pathology in demyelinating disease.