Differential effect of chronic undernutrition on the fiber type composition of fascicles in the extensor digitorum longus muscles of the rat

Chronic Undernutrition Differentially Changes Muscle Fiber Types Organization and Distribution in the EDL Muscle Fascicles

“…In this study, we analyzed the fractal organization of fiber types in fascicles of the EDLm from well-nourished and undernourished rats. Our previous results (Vázquez-Mendoza et al, 2017) indicate that each fascicle in the EDLm, from both well-nourished and undernourished rats, showed a particular composition of fibers types. The relative proportion of intermediate and fast fibers in undernourished fascicles F2 and F4 had no significant differences with that of control fascicles, while the relative proportion of fiber types in fascicles F3 and F5 showed notorious differences with respect to controls (see Table 1), being the sequential order of fascicles affected by chronic undernutrition as follows: F3>F5>F4=F2.…”

“…No supplementary mineral, trace elements or vitamins were added to the food supply of undernourished animals. Further details of these protocols can be found in Ruiz-Rosado et al ( 2013 ) and Vázquez-Mendoza et al ( 2017 ).…”

“…Concrete examples of this type of problem are, determining which gene is responsible for a certain disease (microarray data classification; Cristianini and Shawe-Taylor, 2000;Schölkopf et al, 2004), and face and handwriting recognition (pattern classification; Duda et al, 2012;Devroye et al, 2013). The theory developed around this type of problems is nowadays known as Learning Theory (Vapnik, 1998;Cucker and Zhou, 2007) and its application was boosted thanks to the accessibility of modern computers capable of performing fast calculations. Put plainly, the exact problem we are concerned here with is that of fitting a spatial distribution function to a finite set of points on the plane.…”

“…This organization can be altered by disease, inadequate nutrition, exercise or injury, modifying their contractile and structural properties. Yet we found practically no studies oriented to investigate the organization of fiber types in skeletal muscles and how natural or pathological conditions can modify it, specifically in the case of the extensor digitorum longus muscle (EDLm), which is composed in four fascicles (F2, F3, F4, and F5) with different fiber composition, metabolism, and size (Balice-Gordon and Thompson, 1988 ; Kissane et al, 2016 ; Vázquez-Mendoza et al, 2017 ). This particular muscle participates in the extension of toes (each fascicle extends a single toe, the F2 extends toe 2, the F3 extends toe 3, and so on) and in the dorsiflexion of the ankle in the rat.…”

“…Recently, it has been illustrated elsewhere that chronic undernutrition exerts a differential effect on the relative fiber type composition in the EDLm fascicles (Vázquez-Mendoza et al, 2017 ). Particularly, it was observed that the third fascicle (F3) was more affected than the others, being the sequential order of effects as follows: F3>F5>F4=F2.…”