Muscle Fiber Differentiation and Growth Patterns During Hyperplasia and Hypertrophy in the Ricefield Eel Regulated by Myogenic Regulatory Factors

Abstract

Muscle growth is mainly achieved by two processes, hyperplasia (fiber number increase) and hypertrophy (fiber size increase), and is regulated by the myogenic regulatory factor (MRF) family. The muscle fiber composition and expressional patterns of the four MRFs (Myf5, MRF4, MyoD, and myogenin [MyoG]) were characterized in the white muscle of Ricefield Eels Monopterus albus ranging from 5 to 180 g. Results showed that the mean muscle fiber diameters gradually increased as body mass increased from 5 to 114 g. The small muscle fibers (diameter < 20 μm) were found in the highest ratio in 5-45-g eels; most of the fibers ranged from 20 to 60 μm for 64-104-g fish; and muscle mainly consisted of fibers over 60 μm in 114-180-g fish. The expression of Myf5 and MyoD increased continuously at the stages mainly consisting of the small and medium muscle fibers. Expression of MRF4 and MyoG was low at the stages with high ratios of small muscle fibers, but their expression levels increased at the stages with high ratios of medium muscle fibers. The expression levels of the four MRFs exhibited a regulatory effect on the process of muscle hyperplasia or hypertrophy. The data indicated that hyperplasia was the major event at the earlier stages of the Ricefield Eel, whereas hypertrophy occurred at later developmental stages. The results of our study provide valuable knowledge regarding muscle development in Ricefield Eels.

Lysine effect on the characterization of fillet, by-products, residues, and morphometry of tambaqui Colossoma macropomum (Cuvier, 1818)

“…In addition to the anatomical aspects of the fish body, the yield of the fillet is linked to other conditions, including the weight of residues, sex of the animal, body chemical composition, as well as the human and machines' ability in the filleting process (Contreras-Guzmán 1994, Leonardth et al 2006, Basso & Ferreira 2011. In this context, lysine is inserted in the metabolic process of stretching the myocytes that make up the fillet and thus acts on the hypertrophy and unfolding of the tissue and on the hyperplasia of the cells that, in fish, operate concomitantly and are controlled by factors such as species, phase of life and nutrition of the fish (Aguiar et al 2008, Valente et al 2013, Michelato et al 2016, Chu et al 2018.…”

Identification of Key Genes and Biological Pathways Associated with Skeletal Muscle Maturation and Hypertrophy in Bos taurus, Ovis aries, and Sus scrofa

“…Skeletal muscle development represents a complex process, which involves the alteration of the growth of muscle cells, as well as the differentiation and maturation of muscle fiber, including hypertrophy—an increase in the size of muscle fibers [ 16 ]. Muscle hyperplasia (an increase in number of cells) and hypertrophy (muscle fiber growth in terms of length and diameter) both depend on the proliferation of myoblasts [ 17 ].…”

A Comprehensive Analysis of Fibrillar Collagens in Lamprey Suggests a Conserved Role in Vertebrate Musculoskeletal Evolution

“…The exact role of fibrillar collagens during muscle development in vertebrates is unclear. It is thought that the lateral and dorsoventral ends of the dermomyotome are a source of muscle fibers for secondary myogenesis, also known as stratified hyperplasia, and that these muscle fibers will have a distinct composition compared to the primary myofibers ( Barresi et al, 2001 ; Georgiou et al, 2016 ; Chu et al, 2018 ). The presence of specific collagens in the medial or lateral domains of the dermomyotome indicate that, by these developmental stages, they are likely beginning to differentiate between the dermis and these secondary muscle fibers.…”