Effect of weightlessness on the ultrastructure of rat striated muscles

Abstract

The uttrastructure of rat striated muscles fixed on the 13th day of space flight was studied. It was found that adaptive atrophic and degenerative changes occur in parallel with atypical cellular and intracellular regeneration. The muscles are not completely restored after a 14day readaptation on the Earth.

Influence of Space Flight Factors on the Ultrastructure of Rat Diaphragm Muscle

“…However, there is evidence that speed and power characteristics of the respiratory muscles are reduced during the space fl ight [3,5], which manifested in reduced peak expiratory fl ow rate and especially of peak inspiratory volume rate (by 15-20%) and maximum voluntary ventilation by 20-30%. It can be hypothesized that adaptation to weightlessness is associated with structural and metabolic changes in the diaphragmatic muscle (similarly to other skeletal muscles).…”

“…The study of the system of external respiration in animals (rats) subjected to antiorthostatic hypokinesia for modeling the long-term effects of weightlessness showed that the main mechanism of detected changes is underlain by functional insuffi ciency of the diaphragm due to deterioration of its contractility and impaired excitation-contraction coupling in muscle fi bers in the diaphragm [1][2][3][4].…”