Study of the biomolecular composition of skeletal muscle fibres affected by different types of pathology using by FTIR microspectroscopy.

Myopathies, a group of muscle disorders with varied etiologies, cause significant alterations in muscle tissue biomolecular composition. Accurate differentiation of myopathies is essential for effective diagnosis, treatment and prognosis. Fourier-transform infrared microspectroscopy (microFTIR) is a valuable, non-destructive method for analysing the main biological macromolecules at the microscopic level. Therefore, it may offer insight into the investigation of both primary and secondary myopathies. In our work we use microFTIR to identify unique spectral markers associated with disease progression. For this purpose, muscle tissues from patients diagnosed with dystrophy and myopathy, as well as control tissues, were subjected to probing. The results reveal significant differences in the distribution of lipid, protein, and nucleic acid absorption bands among the sample groups, particularly in regions associated with muscle fibre and connective tissue structure. Notably, vibrational bands at ∼1043, 1388, and 2873 cm-1 assigned to nucleic acids, fatty acids and lipids, respectively showed highest discriminative power in distinguishing pathological from control tissues. In addition, the use of synchrotron radiation FTIR microspectroscopy enabled precise analysis of endomysium-specific changes. This work demonstrates the potential of microFTIR as a novel diagnostic tool for myopathy, offering an early-stage insight into muscle degradation that can support histopathological diagnosis. The ability of microFTIR to detect subtle biomolecular changes represents a promising step forward in non-invasive diagnostics of muscle disorders.