Format

Send to

Choose Destination
PLoS One. 2014 Jun 9;9(6):e99656. doi: 10.1371/journal.pone.0099656. eCollection 2014.

Delayed fracture healing and increased callus adiposity in a C57BL/6J murine model of obesity-associated type 2 diabetes mellitus.

Author information

1
Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, New York, United States of America; School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, New York, United States of America.
2
Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, New York, United States of America.
3
Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, New York, United States of America; Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, New York, United States of America.
4
Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, New York, United States of America; Department of Biostatistics and Computational Biology, University of Rochester Medical Center, Rochester, New York, United States of America.
5
Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, New York, United States of America; Department of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, New York, United States of America; Department of Biomechanical Engineering, University of Rochester, Rochester, New York, United States of America.
6
Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, New York, United States of America; Department of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, New York, United States of America.

Abstract

INTRODUCTION:

Impaired healing and non-union of skeletal fractures is a major public health problem, with morbidity exacerbated in patients with diabetes mellitus (DM). DM is prevalent worldwide and affects approximately 25.8 million US adults, with >90% having obesity-related type 2 DM (T2DM). While fracture healing in type 1 DM (T1DM) has been studied using animal models, an investigation into delayed healing in an animal model of T2DM has not yet been performed.

METHODS:

Male C57BL/6J mice at 5 weeks of age were placed on either a control lean diet or an experimental high-fat diet (HFD) for 12 weeks. A mid-diaphyseal open tibia fracture was induced at 17 weeks of age and a spinal needle was used for intra-medullary fixation. Mice were sacrificed at days 7, 10, 14, 21, 28, and 35 for micro-computed tomography (μCT), histology-based histomorphometry and molecular analyses, and biomechanical testing.

RESULTS:

HFD-fed mice displayed increased body weight and impaired glucose tolerance, both characteristic of T2DM. Compared to control mice, HFD-fed mice with tibia fractures showed significantly (p<0.001) decreased woven bone at day 28 by histomorphometry and significantly (p<0.01) decreased callus bone volume at day 21 by μCT. Interestingly, fracture calluses contained markedly increased adiposity in HFD-fed mice at days 21, 28, and 35. HFD-fed mice also showed increased PPARγ immunohistochemical staining at day 14. Finally, calluses from HFD-fed mice at day 35 showed significantly (p<0.01) reduced torsional rigidity compared to controls.

DISCUSSION:

Our murine model of T2DM demonstrated delayed fracture healing and weakened biomechanical properties, and was distinctly characterized by increased callus adiposity. This suggests altered mesenchymal stem cell fate determination with a shift to the adipocyte lineage at the expense of the osteoblast lineage. The up-regulation of PPARγ in fracture calluses of HFD-fed mice is likely involved in the proposed fate switching.

PMID:
24911161
PMCID:
PMC4049817
DOI:
10.1371/journal.pone.0099656
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Public Library of Science Icon for PubMed Central
Loading ...
Support Center