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Szulc-Lerch K, Yeung J, de Guzman AE, Egan S, Yee Y, Fernandes D, Lerch JP, Mabbott DJ, Nieman BJ. Exercise promotes growth and rescues volume deficits in the hippocampus after cranial radiation in young mice. NMR Biomed 2023; 36:e5015. [PMID: 37548099 DOI: 10.1002/nbm.5015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 07/12/2023] [Accepted: 07/13/2023] [Indexed: 08/08/2023]
Abstract
Human and animal studies suggest that exercise promotes healthy brain development and function, including promoting hippocampal growth. Childhood cancer survivors that have received cranial radiotherapy exhibit hippocampal volume deficits and are at risk of impaired cognitive function, thus they may benefit from regular exercise. While morphological changes induced by exercise have been characterized using magnetic resonance imaging (MRI) in humans and animal models, evaluation of changes across the brain through development and following cranial radiation is lacking. In this study, we used high-resolution longitudinal MRI through development to evaluate the effects of exercise in a pediatric mouse model of cranial radiation. Female mice received whole-brain radiation (7 Gy) or sham radiation (0 Gy) at an infant equivalent age (P16). One week after irradiation, mice were housed in either a regular cage or a cage equipped with a running wheel. In vivo MRI was performed prior to irradiation, and at three subsequent timepoints to evaluate the effects of radiation and exercise. We used a linear mixed-effects model to assess volumetric and cortical thickness changes. Exercise caused substantial increases in the volumes of certain brain regions, notably the hippocampus in both irradiated and nonirradiated mice. Volume increases exceeded the deficits induced by cranial irradiation. The effect of exercise and irradiation on subregional hippocampal volumes was also characterized. In addition, we characterized cortical thickness changes across development and found that it peaked between P23 and P43, depending on the region. Exercise also induced regional alterations in cortical thickness after 3 weeks of voluntary exercise, while irradiation did not substantially alter cortical thickness. Our results show that exercise has the potential to alter neuroanatomical outcomes in both irradiated and nonirradiated mice. This supports ongoing research exploring exercise as a strategy for improving neurocognitive development for children, particularly those treated with cranial radiotherapy.
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Affiliation(s)
- Kamila Szulc-Lerch
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Canada
| | - Jonas Yeung
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Canada
- Translational Medicine, Hospital for Sick Children, Toronto, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
| | - A Elizabeth de Guzman
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Canada
- Translational Medicine, Hospital for Sick Children, Toronto, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
- Functional Neuroimaging Laboratory, Istituto Italiano di Tecnologia, Rovereto, Italy
| | - Shannon Egan
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Canada
- Translational Medicine, Hospital for Sick Children, Toronto, Canada
| | - Yohan Yee
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
- Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Canada
| | - Darren Fernandes
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
- Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Canada
| | - Jason P Lerch
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
- Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Canada
- Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, UK
| | - Donald J Mabbott
- Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Canada
- Department of Psychology, Hospital for Sick Children, Toronto, Canada
| | - Brian J Nieman
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Canada
- Translational Medicine, Hospital for Sick Children, Toronto, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
- Ontario Institute for Cancer Research, Toronto, Canada
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