Cross-Sectional Nakagami Images in Passive Stretches Reveal Damage of Injured Muscles

Figure 6

The normal and injured muscles were passively stretched and fixed at 0, 20, and 40% of deformation to show the histological appearance of muscle and collagen fibers (a). Hematoxylin and eosin (H&E) staining revealed morphological and compositional changes (left) among different stains in normal and injured muscles. Immunohistochemistry (IHC) staining of type I (middle) and type III (right) collagen fibers (brown color) showed the rupture of connective collagen fibers (open arrow). The cross-sectional area of the muscle fiber decreased when normal muscle was subjected to passive stretch, whereas increased area was found in the muscle fibers of injured tissue. The quantified results demonstrated significant decreases in muscle density in injured muscles under passive stretch at 20 and 40% strains (b). Increased pixel numbers for zero scatterer within the region of interest (ROI) were also observed in injured muscles when deformation by passive stretch was increased (c). M: muscle fiber; solid arrow: intact collagen fibril; open arrow: ruptured fibril; open triangle: endomysium around the muscle fiber. Bar in H&E image = 400 μm. Bar in IHC image = 50 μm.

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