Histomorphologic changes in expanded skeletal muscle in rats.

Tissue expansion is one of the powerful tools for various reconstructive procedures and has proven to provide more available local tissues. However, limited attention has been given to the characteristics of expanded skeletal muscle. Using a rat model (n=41), we expanded the rat gracilis muscle and investigated the histomorphologic changes in the expanded skeletal muscle. By expansion, the gracilis muscle after 3 weeks increased 50.4 to 58.4 percent in length and 60.5 percent in width and decreased 39.0 to 42.0 percent in thickness. Histologically, the expanded muscle demonstrated a normal striation and no signs of inflammation or necrosis. The cross-sectional areas of muscle fibers indicated that expanded muscle consisted of predominantly smaller fibers