Effect of Myostatin SNP on muscle fiber properties in male Thoroughbred horses during training period

Abstract

Variants of the Myostatin gene have been shown to have an influence on muscle hypertrophy phenotypes in a wide range of mammalian species. Recently, a Thoroughbred horse with a C-Allele at the g.66493737C/T single-nucleotide polymorphism (SNP) has been reported to be suited to short-distance racing. In this study, we examined the effect of the Myostatin SNP on muscle fiber properties in young Thoroughbred horses during a training period. To investigate the effect of the Myostatin SNP on muscle fiber before training, several mRNA expressions were relatively quantified in biopsy samples from the middle gluteal muscle of 27 untrained male Thoroughbred horses (1.5 years old) using real-time RT-PCR analysis. The remaining muscle samples were used for immunohistochemical analysis to determine the population and area of each fiber type. All measurements were revaluated in biopsy samples of the same horses after a 5-month period of conventional training. Although the expressions of Myostatin mRNA decreased in all SNP genotypes, a significant decrease was found in only the C/C genotype after training. While, expression of VEGFa, PGC1α, and SDHa mRNAs, which relate to the biogenesis of mitochondria and capillaries, was significantly higher (54-82%) in the T/T than the C/C genotypes after training. It is suggested that hypertrophy of muscle fiber is directly associated with a decrease in Myostatin mRNA expression in the C/C genotype, and that increased expressions of VEGFa, PGC1α, and SDHa in the T/T genotype might be indirectly caused by the Myostatin SNP.

Comprehensive genome and transcriptome analyses reveal genetic relationship, selection signature, and transcriptome landscape of small-sized Korean native Jeju horse

“…The A allele (0.89) and Type I fibres predominated in the JH (Table 5). Myostatin, encoded by the MSTN gene, limits skeletal muscle mass by controlling and regulating the growth and number of muscle fibres 76–78 . Variations in MSTN are implicated in muscle fibre composition in horses 73,79–81 .…”

Detection of Indiscriminate Genetic Manipulation in Thoroughbred Racehorses by Targeted Resequencing for Gene-Doping Control

“…In both racing whippets and thoroughbred racehorses, naturally occurring variants of the MSTN gene affect racing performance [ 44 , 45 ]. In thoroughbred horses, where this phenomenon is well-characterized, the variant alters the amount and composition of muscle fiber types [ 46 , 47 ]. Thus, the MSTN gene is an obvious target for gene editing in racehorses, and it was important to show that our screening method would be able to detect MSTN gene editing.…”

Flexibility of equine bioenergetics and muscle plasticity in response to different types of training: An integrative approach, questioning existing paradigms

“…In human sports and training science, a lot of information is available about the effect of different types of training approaches on muscle plasticity and shifts in muscle fiber type composition [7,9,11,14,15,26,36]. In equine sports medicine, the number of studies, comparing plasticity and muscle fiber type composition shifts in response to different types of training is growing rapidly [38][39][40][41][42][43][44][45][46][47][48][49][50][51][52]. Still, equine studies focusing on shifts in the muscle metabolic fingerprint in response to training are very scarce [23,[53][54][55].…”