Poster Presentation 33rd ASM of the Australian & New Zealand Bone & Mineral Society 2023

High-intensity interval training mildly improves trabecular bone microarchitecture in adult male C57BL/6 mice (#201)

Audrey Chan 1 , Navabeh Zarekookandeh* 2 , Martha Blank 3 , James Broatch 2 , David Bishop 2 , Natalie Sims 3 , Gordon Lynch 1 , Itamar Levinger 2
  1. Centre for Muscle Research, Department of Anatomy and Physiology, School of Biomedical Sciences, The University of Melbourne, Parkville, VIC, Australia, Melbourne
  2. Victoria University, Institute for Health and Sport, Victoria University, Melbourne, VIC, Australia
  3. Bone Cell Biology and Disease Unit, St. Vincent’s Institute of Medical Research, Fitzroy, VIC, Australia, Melbourne, VIC, Australia

Objective

Ageing is associated with a reduction in bone quality, and exercise, particularly high-intensity exercise, may improve bone quality. We tested the hypothesis that high-intensity interval training (HIIT) would improve bone microarchitecture in adult mice.

Methods

Adult mice (52-week-old male, C57BL/6) were randomly allocated to either sedentary (n=6) or high-intensity interval training (HIIT, n=8) groups. HIIT group underwent 4x4 minutes of treadmill running (0° incline, 85-90% individual maximum speed) 3 x per week for 6 weeks. Mice in the sedentary group were placed on a stationary treadmill for the same duration. Younger mice (12-week-old male, C57BL/6, n=7) served as a control group. Post-intervention, mice were euthanised; tibiae were then dissected, fixed in 4% paraformaldehyde, and analysed by micro-CT. Trabecular bone was assessed in the metaphysis, and cortical bone analysed slice-by-slice along the central 80% of the bone length.

Results

Adult mice exhibited significantly less trabecular bone mass than younger mice. There were also site-specific differences in the cortical bone structure with age, including greater cross-sectional area, lower normalised bone area, and lower cortical thickness. HIIT did not affect any cortical bone parameters; it also did not alter trabecular bone volume, thickness, or number, compared to sedentary mice. Trabecular separation was significantly higher (by 44%) in adult sedentary mice compared to young mice. In contrast, trabecular separation in the HIIT group was only 16% higher than in young mice, which was not statistically significant. The degree of anisotropy was also significantly lower in the HIIT group compared to both young and adult sedentary mice, indicating greater diversity in trabecular network directionality with HIIT. 

Conclusions

Ageing is associated with significant changes to bone microarchitecture and HIIT may be used as a tool to attenuate the effect of ageing on trabecular bone, but not cortical bone, in adult male mice.

64b9ddb249ce2-Fig+1+Audrey.jpg