Musculoskeletal System

Skeletal Muscle - Degeneration

    Narrative
    Skeletal muscle-Degeneration in a male Harlan Sprague-Dawley rat from a subchronic study. A central myofiber is swollen and hypereosinophilic(arrows), and afragmented segment of another fiber (arrowhead) demonstrates segmental degeneration.
    Skeletal muscle-Degeneration in a male Harlan Sprague-Dawley rat from a subchronic study. An enlarged, hypereosinophilic muscle fiber with subtle vacuolation is present in an otherwise normal muscle bundle.
    Skeletal muscle-Degeneration in a male Harlan Sprague-Dawley rat from a subchronic study. A rounded fiber contains multiple peripheral nuclei, a single internal nucleus, and abundant cytoplasmic vacuoles.
    Skeletal muscle-Degeneration in a male Harlan Sprague-Dawley rat from a subchronic study. Multiple macrophages and interstitial cells have phagocytized degenerative portions of an enlarged muscle fiber.
    Skeletal muscle-Degeneration in a male F344/N rat from a chronic study. In this cross section of muscle, several adjacent muscle fibers exhibit multiple features of degeneration;increased sarcolemmal nuclei are indicative of an early regenerative response.
    Skeletal muscle-Degeneration in a male Harlan Sprague-Dawley rat from a subchronic study. Degeneration is represented by a swollen, hyalinized, and partly fragmented muscle fiber.
    Skeletal muscle-Degeneration in a male Harlan Sprague-Dawley rat from a subchronic study. A fragmented and partly hyalinized muscle fiber has lost its striations and is accompanied by early infiltration of macrophages.

    Authors

    Torrie A. Crabbs, DVM, DACVP
    Pathologist
    Experimental Pathology Laboratories, Inc.
    Research Triangle Park, NC  

    Reviewers

    Philip H. Long, DVM, PhD, DACVP
    Presiden and Senior Pathologist
    Vet Path Services, Inc.
    Mason, OH

    Amy Brix, DVM, PhD, DACVP
    Senior Pathologist
    Experimental Pathology Laboratories, Inc.
    Research Triangle Park, NC

    Robert R. Maronpot, DVM, MS, MPH, DACVP, DABT, FIATP
    Senior Pathologist
    Experimental Pathology Laboratories, Inc.
    Research Triangle Park, NC