A novel rat tail disc degeneration model induced by static bending and compression

Area of Science:

• Biomedical Engineering
• Orthopedics
• Regenerative Medicine

Background:

• Intervertebral disc degeneration (IVDD) is a significant health concern.
• Existing models may not fully replicate the biomechanical forces involved in IVDD.
• A new rat tail model was developed to investigate IVDD under static loading.

Purpose of the Study:

• To establish and validate a rat tail model for inducing intervertebral disc degeneration.
• To observe the morphological and biological changes in intervertebral discs subjected to static bending and compression.
• To assess the impact of varying compression loads on disc degeneration.

Main Methods:

• Twenty Sprague-Dawley rats were divided into control, sham, and two loading groups (1.8 N and 4.5 N).
• Static bending and compression were applied to coccygeal intervertebral discs using external devices.
• Magnetic resonance imaging (MRI), histology, and quantitative real-time PCR (qRT-PCR) were used for analysis on day 14.

Main Results:

• Disc degeneration severity increased with higher compression loads.
• Morphological changes, including disorganization of the nucleus pulposus and annulus fibrosus, were observed in loaded groups.
• Gene expression analysis revealed altered levels of matrix metalloproteinases (MMPs) and extracellular matrix components, with significant differences in loaded groups compared to controls.

Conclusions:

• Static bending and compression effectively induce progressive intervertebral disc degeneration in the rat tail model.
• This model provides a valuable tool for studying the biological mechanisms of disc degeneration under complex static loading conditions.
• The findings highlight the role of mechanical stress in the pathogenesis of IVDD.