| This study investigated the presence of axonal injury within cervical facet joint capsules (FJC) exposed to a high-rate (100 mm/s) tensile stretch. The left C5-C6 FJCs of five anaesthetized goats were subjected to a series of tensile tests in 4 mm increments until rupture (the intact right FJCs served as controls). The FJCs were harvested, fixed in 4% buffered paraformaldehyde, embedded in paraffin, and serially sectioned. FJC sections were immunolabeled for neurofilament light chain (NF-L) and beta-amyloid precursor protein (beta-APP). A significantly higher frequency of coupled beta-APP/NF-L immunoreactive sections was found in stretched (23.8%) compared to unstretched FJCs (6.3%, p = 0.02). This finding suggests that high-rate tensile stretch is a mechanism for axonal injury in cervical FJCs, and furthers the understanding of axonal injury in the whiplash pain mechanism. The use of the dual immunolabeling, presents a new method for identifying axonal injury in skeletal tissue. |
