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Updated: Mar 22, 2026
Characterizing Multiscale Mechanical Properties of Brain Tissue Using Atomic Force Microscopy, Impact Indentation, and Rheometry
Published on: September 6, 2016
Longitudinal measurements of postnatal rat brain mechanical properties in-vivo
Alice C Pong1, Lauriane Jugé1, Shaokoon Cheng2
1Neuroscience Research Australia, Margarete Ainsworth Building, Barker Street, Randwick NSW 2031, Australia; University of New South Wales, School of Medical Sciences, Wallace Wurth Building, Kensington, NSW 2052, Australia.
Insights
Pediatric brain mechanical properties increase from week one to week two and then decrease by week six. These changes in brain tissue stiffness occur during early development and adolescence.
Area of Science:
- Neuroscience
- Biomedical Engineering
- Developmental Biology
Background:
- Pediatric brain tissue mechanical properties are crucial for understanding neural injury mechanisms.
- Limited data exists on how these properties evolve during postnatal development.
Purpose of the Study:
- To investigate in-vivo changes in brain mechanical properties during early postnatal development in a rat model.
- To correlate mechanical property changes with underlying microstructural tissue alterations.
Main Methods:
- Longitudinal in-vivo measurement of rat brain viscoelastic properties using magnetic resonance elastography (MRE) at 800Hz.
- Histological assessment of myelination and cell density at five time points from postnatal week one to six.
- Statistical analysis using generalized linear models with pairwise comparisons.
Main Results:
- Cortical gray matter shear modulus increased significantly from week one to two, stabilized until week four, and decreased by week six.
- Deep gray matter stiffness increased from week one to four and then decreased by week six.
- No direct correlation was found between mechanical property changes and histological observations.
Conclusions:
- Rat brain tissue shear modulus exhibits dynamic changes during postnatal development, initially increasing and subsequently decreasing.
- These findings provide insights into the mechanical development of the brain during periods analogous to human childhood and adolescence.
Abstract:
Information on pediatric brain tissue mechanical properties and, more pertinently, how they change during postnatal development remains scarce despite its importance to investigate mechanisms of neural injury. The aim of this study is to determine whether brain mechanical properties change in-vivo during early postnatal development in a rat model. Rat brain viscoelastic properties were measured longitudinally in ten healthy Sprague Dawley rats at five different time points from postnatal week one to week six using magnetic resonance elastography at 800Hz. Myelination and cell density were assessed histologically at the same time points to understand how the underlying tissue microstructure may be associated with changes in mechanical properties at different brain regions. Longitudinal changes in each variable were assessed using a generalized linear model with pairwise comparisons of means between weeks. The brain shear modulus in the cortical gray matter at postnatal week one was 6.3±0.4kPa, and increased significantly from week one to week two (pairwise comparison, p<0.01), remained stable from week two to week four and decreased significantly by week six (pairwise comparison, p<0.001). In the deep gray matter, brain tissue stiffness at postnatal week one was 6.1±2.0kPa, and increased significantly from one to week four (pairwise comparison, p<0.05) before decreasing significantly by week six (pairwise comparison, p<0.001). Stiffness changes were not directly correlated to histological observations. These data suggest that brain tissue shear modulus initially increases during a period equivalent to early childhood, and then decreases during a period equivalent to adolescence.
