Multivariate modelling

Multivariate modelling of trapezius muscle proteins related to myalgia

In this project we conduct research into what differences may exist between healthy trapezius muscles and those causing pain. Muscle biopsies from both healthy patients and those with trapezius myalgia are used, and they are analysed for hundreds of different proteins. The figures corresponding to the quantities of different proteins present in each muscle are used to make mathematical models of how all proteins are connected in healthy muscles and those causing pain.

Several hypotheses surrounding how strain-related injuries come about are based on the notion that different chemical substances are produced in the muscles during prolonged muscle activity. Exactly which chemical substances these may be have been tested in the course of many studies, but none have proven convincingly which substances are important, and research is still at the hypothesis stage.

In this project, muscle biopsies from both healthy people and patients with trapezius myalgia are examined with regard to the protein composition. Proteins from the biopsies are separated onto gels, first by isoelectric point and then by molecular weight in accordance with 2-DIGE (Two dimensional gel electrophoresis). Before the proteins are grouped onto the same gel, each group is marked with different fluorescent colours (cyanine colours). The intensity of each colour is measured, providing a link between the two groups. As standard, a mix of the two tests is used, which is coloured in with an additional cyanine colour. The proteins are removed from the gels and are first analysed with a mass spectrometer (MALDI-TOF-MS).

Based on the presence of different proteins, multivariate models are built for the purpose of investigation how different proteins correlate with and vary from one another.