In a study from Tokyo Metropolitan University, it was found that a protein known as platelet-derived growth factor subunit B (PDGF-B), which is continually produced by skeletal muscle cells, aids in muscle repair by promoting the development of myoblasts, or muscle stem cells.

Researchers learned that PDGF-B also encourages muscle fibre growth. They found that this correlated with a more muscular contraction of the fibers. The drugs they have discovered have the potential to transform the way we treat muscular injuries and atrophy.

Small proteins known as myokines are secreted by skeletal muscle cells. They perform various tasks and can influence cells nearby and distant from the site of their creation. Although a complete understanding of how myokines affect cellular processes is still far from obvious, they are thought to be crucial for exercise-related body activities, particularly preserving muscle tissue.

According to comprehensive investigations, a myokine PDGF-B, is constitutively released by skeletal muscles, or without any stimulus. Researchers looked into how myokines alter and how muscle cells behave. They subjected myoblasts (which are precursor cells that later develop into muscle fibres) and exposed them to PDGF-B. They were able to demonstrate unequivocally how PDGF-B increased myoblast proliferation.

Additionally, they discovered that differentiated cells were affected by PDGF-B. They exposed myotubes, (a stage in forming muscle fibres) to the same myokine. Under a microscope, the myotubes that had undergone this treatment showed noticeably increased maturation and a visible increase in diameter. Additionally, they expressed more myosin-heavy chain, a crucial component of myosin′s protein structure and the molecular engine for muscle contraction. They thus concluded that, PDGF-B promotes muscle growth and increases muscle strength.

(Source: https://www.hindustantimes.com/lifestyle/health/secreted-protein-aids-in-muscle-growth-and-repair-research-101673775376982.html)