title: Reliable determination of training-induced alterations in muscle fiber composition in human skeletal muscle using quantitative polymerase chain reaction.
abstract: Determination of muscle fiber composition in human skeletal muscle biopsies is often performed using immunohistochemistry, a method that tends to be both time consuming, technically challenging, and complicated by limited availability of tissue. Here, we introduce quantitative reverse transcriptase polymerase chain reaction (qRT-PCR)-based Gene-family profiling (GeneFam) of myosin heavy chain (MyHC) mRNA expression as a high-throughput, sensitive, and reliable alternative. We show that GeneFam and immunohistochemistry result in similar disclosures of alterations in muscle fiber composition in biopsies from musculus vastus lateralis and musculus biceps brachii of previously untrained young women after 12 weeks of progressive strength training. The adaptations were evident as (a) consistent increases in MyHC2A abundance; (b) consistent decreases in MyHC2X abundance; and (c) consistently stable MyHC1 abundance, and were not found using traditional reference gene-based qRT-PCR analyses. Furthermore, muscle fiber composition found using each of the two approaches was correlated with each other (r = 0.50, 0.74, and 0.78 for MyHC1, A, and X, respectively), suggesting that GeneFam may be suitable for ranking of individual muscle phenotype, particularly for MyHC2 fibers. In summary, GeneFam of MyHC mRNA resulted in reliable assessment of alterations in muscle fiber composition in skeletal muscle of previously untrained women after 12 weeks of strength training.
authors.affiliation: Lillehammer University College, Lillehammer, Norway.
authors.forename: S
authors.initials: S
authors.lastname: Ellefsen
authors.forename: O
authors.initials: O
authors.lastname: Vikmoen
authors.forename: E
authors.initials: E
authors.lastname: Zacharoff
authors.forename: I
authors.initials: I
authors.lastname: Rauk
authors.forename: G
authors.initials: G
authors.lastname: Slettaløkken
authors.forename: D
authors.initials: D
authors.lastname: Hammarström
authors.forename: T A
authors.initials: TA
authors.lastname: Strand
authors.forename: J E
authors.initials: JE
authors.lastname: Whist
authors.forename: M
authors.initials: M
authors.lastname: Hanestadhaugen
authors.forename: G
authors.initials: G
authors.lastname: Vegge
authors.forename: C E
authors.initials: CE
authors.lastname: Fagernes
authors.forename: H
authors.initials: H
authors.lastname: Nygaard
authors.forename: I
authors.initials: I
authors.lastname: Hollan
authors.forename: B R
authors.initials: BR
authors.lastname: Rønnestad
mesh_terms: D000328:Adult; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D007150:Immunohistochemistry; D018995:Myosin Heavy Chains / Q000235:genetics; D010641:Phenotype; D064797:Physical Conditioning, Human / Q000502:physiology*; D052097:Quadriceps Muscle / Q000737:chemistry* / Q000166:cytology; D012333:RNA, Messenger / Q000032:analysis*; D060888:Real-Time Polymerase Chain Reaction; D055070:Resistance Training; D055815:Young Adult
chemical_list: D012333:RNA, Messenger; D018995:Myosin Heavy Chains
keywords: GeneFam; MYH; Normalization; exercise; fiber typing; gene-family profiling; muscle biopsy; real-time RT-PCR; resistance training