Meeting Abstract
Mammalian skeletal muscle contains three morphologically and functionally distinct layers of intramuscular connective tissue: the endomysium, perimysium, and epimysium. This structural arrangement is assumed to be ubiquitous across the animal kingdom; however, detailed morphological studies of connective tissue have been carried out in only a handful of species outside of Mammalia. We used classic muscle decellurization and scanning electron microscope techniques to visualize the morphology of connective tissues in muscles sampled from a range of vertebrates. We tested the hypothesis that a distinct endomysium, perimysium, and epimysium could be identified in all samples. Frog, turkey, rat, and alligator muscle displayed morphologically distinct layers of endomysial, perimysial, and epimysial connective tissue consistent with those described in the literature. Carp muscle was also visualized and displayed a clear endomysium and epimysium, but a distinct perimysium dividing muscles into fascicles was not apparent. Qualitative differences in the density and arrangement of the endomysium and perimysium were apparent across species. These results reveal a greater diversity in connective tissue structure across vertebrate muscle than has previously been described, and suggest that models of connective tissue developed from studies of mammalian muscle may not necessarily be applicable to all species. Supported by NIH grant AR055295.
