A comprehensive study of long-term skeletal changes after spinal cord injury in adult rats

Bone Research, 2015 · DOI: 10.1038/boneres.2015.28 · Published: October 27, 2015

Spinal Cord Injury Musculoskeletal Medicine

Simple Explanation

Spinal cord injury (SCI) can lead to significant bone loss, resembling severe osteoporosis. This study investigates the long-term effects of SCI on bone structure and strength in adult rats to better understand chronic SCI in humans. The study found that SCI causes extreme bone loss in the metaphysis of long bones, while the subchondral part shows milder damage. Bone mass and strength are also reduced in the lower spine but not in the upper arms. SCI inhibits bone formation and increases bone resorption, which contributes to the overall bone damage. These findings could help in developing new treatments for SCI-induced osteoporosis.

Study Duration

16 weeks

Participants

4-month-old Fischer 344 male rats

Evidence Level

Not specified

Key Findings

1
Extreme losses of bone structure and mechanical competence were detected in the metaphysis of sublesional long bones after SCI, while the subchondral part of the same bones showed much milder damage.
2
Marked reductions in bone mass and strength were also observed in sublesional L4 vertebrae but not in supralesional humeri.
3
SCI induced structural and strength damage in both sub- and supralesional long bones.

Research Summary

This study comprehensively analyzed long-term structural and mechanical changes in axial and appendicular bones in adult rats after SCI, revealing site-specific effects of SCI on bone. The research demonstrated sustained inhibition of bone formation and elevation of bone resorption at the chronic stage of SCI, providing mechanistic insight for developing new effective treatments for SCI-induced severe osteoporosis. The findings indicated that trabecular bone is primarily sensitive to local factors, while cortical bone is also sensitive to systemic factors contributing to SCI-induced bone damage.

Practical Implications

Targeted Therapies

The site-specific effects of SCI on bone suggest that treatments should be tailored to address the specific needs of different skeletal regions.

Anabolic Treatments

The sustained inhibition of bone formation indicates that anabolic treatments promoting new bone formation should be pursued for chronic SCI patients.

Clinical Relevance

Using adult rats in the study enhances the clinical relevance of the findings, making them more applicable to human SCI patients.

Study Limitations

1
Used age- and gender-matched naive rats instead of sham-operated rats as controls.
2
Rats never cease longitudinal bone growth, potentially confounding metaphyseal region analysis.
3
Cannot completely exclude the confounding factor of growth on the metaphyseal region.

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