Proteomic study of microbiopsies from women with trapezius muscle pain and from healthy women

Abstract: Trapezius myalgia is a pain condition that usually develops in people with repetitive and stressful work tasks, which can lead to chronic widespread pain (CWP). This work compares protein expression levels in healthy women with those in women who have chronic widespread pain, including pain in the trapezius muscle, by using a proteomic approach.  Twodimensional gel electrophoresis and silver staining with a subsequent digital quantification of protein spots was used to detect spots which had significantly higher protein levels in either group. Preparative gels were made and stained with SYPRO Ruby, the protein spots that were significantly different between the groups were picked from the SYPRO Ruby gels and identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, MALDI-TOF. The optical density of seven protein spots were significantly decreased in the trapezius muscle of the CWP subjects; however the standard deviations were notably high. Five of the seven proteins could be identified as desmin, creatine kinase B-type, serum albumin, heat shock protein beta-1 and slow skeletal muscle troponin T. Apart from serum albumin, all these proteins can possibly be responsible for pain in the trapezius muscle in CWP. In conclusion, this study demonstrates that two-dimensional gel electrophoresis in combination with mass spectrometry is a powerful tool to identify potential biomarkers of musculoskeletal pain in subjects with CWP. The results may provide new insights into the mechanisms and patho-physiology of trapezius myalgia.