Fig. 4

Representative histologic images of healthy control and degenerated tendons. H&E staining (a) of healthy tendons displayed arrays of straight, compact fibers with linear shaped interfascicular inconspicuous nuclei. As degeneration progressed, the fibers started to lose polarity and became thinner and wavy. Tenocytes increased in number and size, and their nuclei changed into ovoid shape. Alcian blue staining (b) of degenerated tendon tissues showed interfascicular ground substances and acid mucopolysaccharides, which are rarely observed in healthy tendons. SP (c) and CGRP (d) immunoreactions were elevated in proportion with the degree of degenerative changes, but healthy tendons showed negative reactions to immunohistochemical staining. Values below the mean Movin score of 17.5 were defined as mild degeneration. Values above the mean Movin score were defined as severe degeneration. SP, substance P; CGRP, calcitonin gene-related peptide; magnification × 400; scale bar = 50 μm