Muscle Hypertrophy Research Paper

Satellite Cell, Muscle Hypertrophy and Exercise

Serife Vatansever1 Burcin Olcucu2

1Abant Izzet Baysal University, School of Physical Education and Sports, Department of Trainer Education, Bolu, Turkey.

2Gaziosmanpasa University, School of Physical Education and Sports, Department of Coaching Education, Tokat, Turkey.

Abstract

Optimal repair and adaptation of skeletal muscle is facilitated by resident satellite cells (satellite cells). Satellite cells are not only responsible for muscle repair and regeneration, but also for hypertrophic growth. The role of satellite cells in muscle hypertrophy has long been a debated issue. In this review we will discuss the role of satellite cells on muscle hypertrophy both in mice as well as in humans.

This accordance is one of the most important features of skeletal muscles. Muscle mass is the primary indicator of muscle strength and it is not stable. There is continuous process that includes the balance between protein synthesis and catabolism, which determines hypertrophy or atrophy (Blaauw et al., 2013).

Increase in muscle proteins during muscle hypertrophy occurs because of either increasing RNA and protein synthesis by existing nuclei or preserving of the same level RNA and protein synthesis from each nuclei and new myonuclei addition to fibers. Because mature muscle fiber myonuclei cannot divide, source of new myonuclei added to fiber is the external of the fiber. Satellite cells are the main donors for the formation of new myonuclei, which is important for muscle hypertrophy that occurs as a reaction to myogenic precursor cell formation, muscle development, muscle regeneration besides exercise, training and hormonal stimulants (Montarras et al., 2013). Nuclei of satellite cells exists under basal lamina. However, unlike real myonuclei they exist out of sarcolemma. Because of their location between sarcolemma and basal lamina, satellite cells can be detected either with electron microscope or marker proteins of sarcolemma and basal lamina. Transcription factors such

However, exercise related skeletal muscle hypertrophy mechanism hasn’t been fully understood (Kadi, et al., 1999a). Some researches have been conducted to associate increases in skeletal muscle nuclei and satellite cells with muscle fiber hypertrophy. It is generally believed that muscle satellite cells are required for skeletal muscle hypertrophy. However, the effect of exercise on satellite cells is still widely investigated (Kadi et al., 2014c).

It has been proven that resistance exercise is an effective strategy to increase muscle mass and strength (Charette et al., 1991; Esmarck et al., 2001; Fiatarone et al., 1994; Frontera et al., 1988; Kosek et al., 2006). Recent research has shown that resistance exercise also affects satellite cell activation (Verdijk et al., 2009b). Snijders et al. (2012) who conducted a research on 8 males with endurance and resistance exercises found that there was a significant increase in satellite cell activation in Type 1 and Type 2 muscle fibers after a single bout of