Zavodovsky D. Structural and mechanical changes of muscle fibers and sarcomers due to ischemic degeneration.

The thesis is devoted to reveal the contraction dynamic characteristics of the rat gastrocnemius muscle under vascular ischemia condition, that allow qualitatively distinguish pathological state from intact muscle, and during fatigue development. Changes of the dynamics of muscle contraction depending on the duration of ischemia and microscopic and ultrastructural study of muscle samples after different ischemia time were also investigated. Conducted in this paper comparative studies indicate the presence of dynamic characteristics of contraction that observed with the use of complex frequency-modulated stimulation signals which in turn allow qualitatively distinguish contraction of ischemic muscle from the intact one, and most importantly, without taking into account the absolute value of the force of contraction. Characteristic features of ischemic muscle fatigue as well were identified. Histological and ultrastructural studies indicate the pathological changes that occur in ischemic damaged striated muscle on the level of sarcomers and muscle cells, and made it possible to assume relationship of structural damage with functional degradation detected with strain-gauge measurements.