Variation in Intrinsic Aerobic Capacity Reveals Distinct Differences in the Maintenance of Rat Knee Joint Integrity.
6 affiliations
- 1Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.
- 2McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, Alberta, Canada.
- 3Carrera de Kinesiología, Departamento de Ciencias de la Salud, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.
- 4Department of Surgery, University of Calgary, Calgary, Alberta, Canada.
- 5Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
- 6Department of Physiology and Pharmacology, College of Medicine and Life Sciences, The University of Toledo, Toledo, Ohio, USA.
Abstract
The objective was to test how intrinsic aerobic capacity affects the articular cartilage, infrapatellar fat pad (IFP), subchondral bone, and synovial membrane of the rat knee joint. Thirty-five 24-week-old male N:NIH rats selectively bred for high aerobic capacity (high-capacity-runner [HCR]; n = 17) and low aerobic capacity (low-capacity-runner [LCR]; n = 18) were fed either a high-fat/high-sucrose (HFHS) diet or a chow diet for 12 weeks. Alterations in articular cartilage, subchondral bone microarchitecture, IFP hypertrophy, and synovial membrane cytokine levels were quantified. Body composition, serum cytokines, and glucose tolerance were assessed at Week 12. Compared to HCR rats, LCR rats had higher modified Mankin scores, bone volume, total volume, bone mineral density, bone volumetric fraction, and trabecular thickness, and lower specific bone surface, bone surface density, and connectivity density. LCR rats also had higher RANTES (Regulated on Activation, Normal T Cell Expressed and Secreted) and lower EGF (epidermal growth factor) levels in synovium analytes. Furthermore, in response to the HFHS diet, there were no differences in adipocyte hypertrophy within the IFP for either the HCR or LCR rats. LCR rats demonstrated hyperglycemia, elevated pro-inflammatory marker levels, and decreased anti-inflammatory marker levels compared to HCR rats. It was concluded that intrinsic high aerobic capacity maintains superior knee joint integrity both with and without an obesogenic dietary challenge, likely due to superior metabolic resistance. Whether intrinsic high aerobic capacity might protect joint degeneration in obesity and metabolic syndrome in other species including humans, warrants investigation.
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BibTeX
@article{tripathi2026variation,
title = {{Variation in Intrinsic Aerobic Capacity Reveals Distinct Differences in the Maintenance of Rat Knee Joint Integrity.}},
author = {Darsh Tripathi and Mauricio Delgado-Bravo and Ruth A Seerattan and Venus Joumaa and David A Hart and Raylene A Reimer and Lauren Gerard Koch and Walter Herzog},
journal = {Journal of orthopaedic research : official publication of the Orthopaedic Research Society},
year = {2026},
month = oct,
doi = {10.1002/jor.70299},
url = {https://europepmc.org/article/MED/42896009},
note = {CC BY},
}
RIS
TY - JOUR
TI - Variation in Intrinsic Aerobic Capacity Reveals Distinct Differences in the Maintenance of Rat Knee Joint Integrity.
AU - Darsh Tripathi
AU - Mauricio Delgado-Bravo
AU - Ruth A Seerattan
AU - Venus Joumaa
AU - David A Hart
AU - Raylene A Reimer
AU - Lauren Gerard Koch
AU - Walter Herzog
PY - 2026
DA - 2026/10/01
JO - Journal of orthopaedic research : official publication of the Orthopaedic Research Society
DO - 10.1002/jor.70299
UR - https://europepmc.org/article/MED/42896009
AB - The objective was to test how intrinsic aerobic capacity affects the articular cartilage, infrapatellar fat pad (IFP), subchondral bone, and synovial membrane of the rat knee joint. Thirty-five 24-week-old male N:NIH rats selectively bred for high aerobic capacity (high-capacity-runner [HCR]; n = 17) and low aerobic capacity (low-capacity-runner [LCR]; n = 18) were fed either a high-fat/high-sucrose (HFHS) diet or a chow diet for 12 weeks. Alterations in articular cartilage, subchondral bone microarchitecture, IFP hypertrophy, and synovial membrane cytokine levels were quantified. Body composition, serum cytokines, and glucose tolerance were assessed at Week 12. Compared to HCR rats, LCR rats had higher modified Mankin scores, bone volume, total volume, bone mineral density, bone volumetric fraction, and trabecular thickness, and lower specific bone surface, bone surface density, and connectivity density. LCR rats also had higher RANTES (Regulated on Activation, Normal T Cell Expressed and Secreted) and lower EGF (epidermal growth factor) levels in synovium analytes. Furthermore, in response to the HFHS diet, there were no differences in adipocyte hypertrophy within the IFP for either the HCR or LCR rats. LCR rats demonstrated hyperglycemia, elevated pro-inflammatory marker levels, and decreased anti-inflammatory marker levels compared to HCR rats. It was concluded that intrinsic high aerobic capacity maintains superior knee joint integrity both with and without an obesogenic dietary challenge, likely due to superior metabolic resistance. Whether intrinsic high aerobic capacity might protect joint degeneration in obesity and metabolic syndrome in other species including humans, warrants investigation.
SN - 0736-0266
SN - 1554-527X
ER -