Hydrogen Peroxide Treatment of Muscle Fibres Inhibits the Formation of Myosin Cross-Bridges.

The molecular mechanism of violation of the contractile function of skeletal muscles caused by oxidative damage to myosin is not fully understood. Using permeabilized fibres from fast (m. psoas) and slow (m. soleus) rabbit muscles, we studied the effect of myosin oxidation on the mechanism of force generation and its calcium regulation. It was found that this treatment simultaneously reduces the maximum force and fibers stiffness without affecting their calcium sensitivity. This suggests that the mechanism of oxidation-related impairment the force-generating ability of fibers consists in suppression of myosin cross-bridges formation and does no affect the characteristics of actin-myosin interaction.