[Protective effect of nitric oxide on cytoskeletal proteins in skeletal muscles under eccentric exercise]

The protective effect of nitric oxide (NO) on the cytoskeletal muscle proteins desmin and dystrophin has been studied under eccentric exercise. Experiments were performed on 28 male Wistar rats, which were divided into four groups: cage control (C, n = 7); group of eccentric exercise (running down a motor-driven treadmill, inclination 16 degrees) (20 m/min, 40 min running) (R, n = 7); eccentric exercise + L-arginine group (RA, n = 7) (with a daily supplementation of 500 mg/kg wt L-arginine for 3 days before the running); and eccentric exercise + L-NAME group (RN, n = 7) (with a daily supplementation of 90 mg/kg wt L-NAME (Nomega-nitro-L-arginine methyl ester, nNOS blocker) for 3 days before the running). It was found that increasing the NO concentration (in RA group) prevents the disruption of the dystrophin layer and decreases the loss of desmin in m. soleus under eccentric contraction, whereas in the R and RN groups the level of damage to dystrophin and desmin was significantly higher compared to the control rats. The inhibition of nNOS (by L-NAME) increases the nNOS mRNA level in the m. soleus, whereas increasing the NO concentration in m. soleus (L-arginine administration) does not affect the level of nNOS mRNA during the eccentric running. It was concluded that NO has a protective action on the cytoskeletal proteins desmin and dystrophin in skeletal muscle under eccentric contraction-induced damage.