Multiscale 3D whole joint cellular and molecular mapping dissects the relationship between structure and pain

Area of Science:

• Biomedical Engineering
• Anatomy
• Neuroscience

Background:

• Understanding joint structure-function relationships is crucial for treating joint diseases and pain.
• Current imaging methods face challenges in visualizing intact joints at multiple scales.
• Elucidating joint pathophysiology requires advanced techniques for detailed anatomical and cellular analysis.

Purpose of the Study:

• To introduce a novel method for 3D immunostaining and optical clearing of intact musculoskeletal joints.
• To enable high-resolution, microscale neurovascular mapping within whole joints across different species.
• To investigate the role of neurovascular changes in joint degeneration and traumatic injury.

Main Methods:

• Development of the musculoskeletal joint immunostaining and clearing (MUSIC) method.
• Application of large-field light sheet microscopy for 3D imaging.
• Analysis of neurovascular distributions in various joint types (temporomandibular, knee, spine) and species (mouse, rat, pig).

Main Results:

• MUSIC enables 3D high-resolution mapping of joint neurovasculature without image coregistration.
• Revealed heterogeneous distributions and novel pathways of neurovascular networks within joints.
• Identified significant joint-wide neurovascular alterations in proteoglycan 4 knockout mice and following traumatic injury, preceding morphological changes.

Conclusions:

• The MUSIC platform provides a powerful tool for multiscale 3D analysis of joint tissues.
• Offers new insights into joint pathophysiology, particularly the interplay between neurovasculature and disease.
• Facilitates research into the mechanisms of joint pain and the development of targeted therapies.