Abstract: BACKGROUND: Serum-specific biomarkers between normal healthy individuals and populations with developmental cervical canal stenosis (Qi deficiency and blood stasis syndrome) have not been fully defined.
OBJECTIVE: To screen and identify the potential biomarkers of developmental cervical canal stenosis with Qi deficiency and blood stasis.
METHODS: Serum samples were collected from nine patients with developmental cervical canal stenosis with Qi deficiency and blood stasis and eight healthy people. Differentially expressed proteins in serum were screened and identified using isotope relative labeling and absolute quantification combined with liquid chromatography tandem mass spectrometry. Western blot was used to verify some significant differentially expressed proteins. 
RESULTS AND CONCLUSION: A total of 61 differentially expressed proteins (P < 0.05) were identified using tandem mass spectrometry techniques. Compared with the healthy normal population group, 14 differentially expressed proteins such as complement component C1q receptor, apolipoprotein A4, and C-C motif chemokine ligand 18 were significantly upregulated, while 47 differentially expressed proteins such as myosin light chain 3, mitochondrial translation elongation factor, and nucleolar phosphoprotein 1 were significantly downregulated. The results of gene ontology enrichment analysis indicated that these differentially expressed proteins might participate in molecular functions such as regulation of chromosomal tissue, mitochondrial membrane tissue, and muscle system processes. Protein-protein interaction network analysis showed that 38 common differential proteins, including complement component C1q receptor, apolipoprotein A4, C-C motif chemokine ligand 18, myosin light chain 3, mitochondrial translation elongation factor, and nucleolar phosphoprotein 1, were located at functional network nodes between healthy normal individuals and those with developmental cervical canal stenosis (Qi deficiency and blood stasis syndrome), and were closely related to the local energy metabolism of the cervical spine, the production of cervical vertebral osteocytes, and the formation of osteoclasts. The main differentially expressed protein myosin light chain 3 was validated using western blot assay, and the validation results were consistent with the proteomic results. To conclude, the preliminary discovery of differentially expressed proteins in serum between healthy normal individuals and those with developmental cervical canal stenosis (Qi deficiency and blood stasis syndrome) through absolute quantitative technology combined with liquid chromatography tandem mass spectrometry technology suggests that myosin light chain 3 may be a specific serum marker for developmental cervical canal stenosis (Qi deficiency and blood stasis syndrome).

Key words: developmental cervical canal stenosis, Qi deficiency and blood stasis syndrome, tandem mass spectrometry, serum protein marker, proteomics