Affiliations: [a] Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, Park Place, Cardiff, UK | [b] Brain Repair Group, Life Science Building, 3rd Floor, School of Biosciences, Cardiff University, Museum Avenue, Cardiff, UK | [c] Experimental MRI Centre (EMRIC), School of Biosciences, Cardiff University, Museum Avenue, Cardiff, UK | [d] School of Biomedical Sciences, Queen’s Medical Centre, Nottingham University, Nottingham, UK
Correspondence to: Dr. Jessica Steventon, Cardiff University Brain Research Imaging Centre, School of Psychology, CardiffUniversity, Park Place, Cardiff, CF10 3AT, UK. Tel.: +44 02920 870355; firstname.lastname@example.org
Background: Environmental enrichment has been shown to improve symptoms and reduce neuropathology in mouse models of Huntington’s disease (HD); however results are limited to ex vivo techniques with associated shortcomings. In-vivo magnetic resonance imaging (MRI) can overcome some of the shortcomings and is applied for the first time here to assess the effect of a cognitive intervention in a mouse model of HD.
Objectives: We aimed to investigate whether in-vivo high-field MRI can detect a disease-modifying effect in tissue macrostructure following a cognitive enrichment regime.
Methods: YAC128 transgenic and wild type mice were exposed to cognitive enrichment throughout their lifetime. At 20-months old, mice were scanned with a T2-weighted MRI sequence and a region-of-interest (ROI) approach was used to examine structural changes. Locomotor activity and performance on the rotarod and serial discrimination watermaze task were assessed to measure motor and cognitive function respectively.
Results: Mice exposed to cognitive enrichment were more active and able to stay on a rotating rod longer compared to control mice, with comparable rotarod performance between HD enriched mice and wild-type mice. YAC128 mice demonstrated cognitive impairments which were not improved by cognitive enrichment. In-vivo MRI revealed a reduction in the degree of caudate-putamen atrophy in the enriched HD mice.
Conclusions: We provide in vivo evidence of a beneficial effect of environmental enrichment on neuropathology and motor function in a HD mouse model. This demonstrates the efficacy of MRI in a model of HD and provides the basis for an in-vivo non-destructive outcome measure necessary for longitudinal study designs to understand the effect of enrichment with disease progression.
Keywords: Huntington’s Disease, magnetic resonance imaging, cognitive enrichment, mouse model