Matrisome age-related changes in the mouse gastrocnemius muscle

In recent years, thanks to the great development of mass spectrometry (MS)-based high-throughput proteomic techniques, a large-scale protein characterization is less challenging. Proteomic approaches have been successfully applied to SM in different experimental models [21–24]; however, to date, there is little information on ECM proteins and how they change during ageing. The identification and quantification of ECM components and their interactions are es-sential steps to understand the role of the matrisome in sarcopenia. In this context, we combined a proteomic approach (i.e., LC-MS/MS and bioinformatic analyses) with mor-phological and morphometrical evaluations at fluorescence and transmission electron microscopy of the gastrocnemius muscle in adult and old mice. This age range has been selected since it has been observed that most of changes in muscle protein expression take place after middle age. The gastrocnemius muscle was selected for analysis since it is prevalently composed of fast-twitch fibre, which are especially affected by atrophy during aging. Our findings highlighted several modifications of ECM protein composition and organization in old mice, which likely play a role in the alteration of muscle properties during aging.