Algogenic substances and metabolic status in work-related Trapezius Myalgia: a multivariate explorative study
2014 (English)In: BMC Musculoskeletal Disorders, ISSN 1471-2474, Vol. 15, no 357Article in journal (Refereed) Published
Background: This study compares the levels of algesic substances between subjects with trapezius myalgia (TM) and healthy controls (CON) and explores the multivariate correlation pattern between these substances, pain, and metabolic status together with relative blood flow changes reported in our previous paper (Eur J Appl Physiol 108: 657-669, 2010). Methods: 43 female workers with (TM) and 19 females without (CON) trapezius myalgia were - using microdialysis - compared for differences in interstitial concentrations of interleukin-6 (IL-6), bradykinin (BKN), serotonin (5-HT), lactate dehydrogenas (LDH), substance P, and N-terminal propeptide of procollagen type I (PINP) in the trapezius muscle at rest and during repetitive/stressful work. These data were also used in multivariate analyses together with previously presented data (Eur J Appl Physiol 108: 657-669, 2010): trapezius muscle blood flow, metabolite accumulation, oxygenation, and pain development and sensitivity. Results: Substance P was significantly elevated in TM (p=0.0068). No significant differences were found in the classical algesic substances (p: 0.432-0.926). The multivariate analysis showed that blood flow related variables, interstitial concentrations of metabolic (pyruvate), and algesic (BKN and K+) substances were important for the discrimination of the subjects to one of the two groups (R-2: 0.19-0.31, pless than0.05). Pain intensity was positively associated with levels of 5-HT and K+ and negatively associated with oxygenation indicators and IL-6 in TM (R-2: 0.24, pless than0.05). A negative correlation existed in TM between mechanical pain sensitivity of trapezius and BKN and IL-6 (R-2: 0.26-0.39, pless than0.05). Conclusion: The present study increased understanding alterations in the myalgic muscle. When considering the system-wide aspects, increased concentrations of lactate, pyruvate and K+ and decreased oxygenation characterized TM compared to CON. There are three major possible explanations for this finding: the workers with pain had relatively low severity of myalgia, metabolic alterations preceded detectable alterations in levels of algesics, or peripheral sensitization and other muscle alterations existed in TM. Only SP of the investigated algesic substances was elevated in TM. Several of the algesics were of importance for the levels of pain intensity and mechanical pain sensitivity in TM. These results indicate peripheral contribution to maintenance of central nociceptive and pain mechanisms and may be important to consider when designing treatments.
Place, publisher, year, edition, pages
BioMed Central / Springer Verlag (Germany) , 2014. Vol. 15, no 357
Myalgia; Exercise; Human; Mental stress; Microdialysis; Pain
IdentifiersURN: urn:nbn:se:liu:diva-113584DOI: 10.1186/1471-2474-15-357ISI: 000346808400001PubMedID: 25348119OAI: oai:DiVA.org:liu-113584DiVA: diva2:783013
Funding Agencies|Danish Medical Research Council [22-03-0264]; Danish Rheumatism Association [233-1149-02.02.04]; Swedish Research Council [K2011-69X-21874-01-6]; Swedish Council for Working Life and Social Research [2010-0913]2015-01-232015-01-232015-02-11