Structural and Ultrastructural Changes in Skeletal Muscle Tissue After High-Energy Injury in the Early Post-Traumatic Period

The number of mine-blast wounds is increasing sharply worldwide, therefore the assessment of morphogenesis of high-energy damage to limb tissues is one of the important tasks of modern histology. The paper studies striated skeletal muscle tissue after mine-blast avulsion of limb segments to a depth of 6 cm in the first 4 days after injury. Histological (hematoxylin and eosin staining, staining for the duration of fibrin formation), immunohistochemical and immunofluorescent methods (antibodies to CD3, CD20, CD31, CD68, NETs) and transmission electron microscopy are used. Morphometric methods of research are used. It is established that after injury, pathological changes affect both muscle tissue (necrosis, fragmentation of muscle fibers, traumatic edema) and connective tissue of endo- and perimysium (traumatic edema, fibrin impregnation). Ultrastructurally, the cytoskeleton structure (sarcomeres) of muscle fibers is disrupted, myostatillocytes and endothelial cells of muscle tissue capillaries are lost. Local hemodynamic disturbances are manifested by mosaic thromboses, embolism and hemorrhages; spasm of arteries and arterioles is established on the first day, leading to a decrease in tissue perfusion. The spasm partially resolves by the 4th day, which is probably associated with the development of the 2nd period of traumatic disease (torpid phase of traumatic shock). Among leukocytes, CD68+ macrophages react earliest, which is manifested by their extravasation starting from the 2nd day. A similar trend was detected for CD3+ T-lymphocytes. CD20+ B-lymphocytes did not show morphological signs of reactivity during the specified periods.