One of the most noticeable effects of aging is the reduction in skeletal muscle mass and strength (sarcopenia). The metabolic syndrome (MS) is also prevalent in old subjects, but its relevance to skeletal muscle characteristics has poorly been investigated. Immunohistochemical studies were performed with muscle biopsies from young (22 years) and old (73 years) men with and without MS to reveal age-dependent and MS-associated modifications of fiber-type characteristics. Atrophy of type II fibers and altered fiber shape characterized muscle aging in lean healthy men. In contrast, increased cross-sectional area of the most abundant type I and type IIA fibers, and reduced cytochrome c oxidase content in all fiber types, characterized MS. Aging and particularly MS were associated with accumulation of intramyocellular lipid droplets. Although lipids mostly accumulated in type I fibers, matrix-assisted laser desorption/ionization-mass spectrometry imaging of intramyocellular lipids did not distinguish fiber types, but clearly separated young, old, and MS subjects. In conclusion, our study suggests that MS in the elderly persons is associated with alterations in skeletal muscle at a fiber-type specific level. Overall, these fiber type-specific modifications may be important both for the age-related loss of muscle mass and strength and for the increased prevalence of MS in elderly subjects.
In this short communication we describe a specific protocol for SDS-PAGE separation of adult bovine myosin heavy-chain (MyHC) isoforms. The conditions defined in this protocol allow a good separation with a good reproducibility of the four MyHC isoforms (MyHC I, IIa, IIx, IIb) identified in adult skeletal muscle of this species. This procedure uses mini-gel electrophoresis system and does not involve preparation of gradient separating gels. In addition, this protocol can also be applied to the electrophoretic separation of ovine and camel MyHC isoforms.
In agricultural sciences, proteomics has become the new hope for analyzing the meat quality traits that are closely related to the skeletal muscle traits. 2-DE muscle maps of many species have been recently reported and used to find molecular markers of meat quality traits. However, one limitation of 2-DE based analyses is due to the limited alkaline protein separation. Considering this problem, there is a need to use recent advances that have markedly improved the 2-DE based analysis of alkaline proteins. Hence, the present study provides additional information concerning the alkaline proteome of bovine skeletal muscle by using an appropriate protocol to characterize proteins over the entire range of pH 7-11. A total of 32 distinct gene products corresponding to 60 protein spots were identified by PMF and grouped in seven categories according to their main function. This 2-D map will contribute to muscle proteome studies since a significant portion of proteins is in the alkaline pH range.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.