[Locomotion of dystrophin-deficient mice]

The purpose of our study was to make a comparison of the motor function between murine dystrophy mice (MDX mice) and C57BL/10ScSn control mice. The locomotor activities of mice were measured by an animal three-dimension optical monitor. Measurements were performed at ages of 21, 45 and 60 days. Animals were tested in a dark and peaceful environment under room temperature (25 degrees C-27 degrees C) at night for an hour. Results showed that the most important differences were in data on vertical activities. Among 15 variables of locomotor activity detected by the optical activity monitor, the MDX mice and control mice at age 21 days showed significant differences in 12 variables. However, the MDX mice and control mice at age 45 days revealed significant differences in only 7 variables. The MDX mice and control mice at age 60 days had significant differences for only one variable. The results may be explained by the fact that dystrophin-deficient mice undergo more severe dystrophic degeneration at an early age (5 weeks) and new regeneration of their muscle fibres is prevalent. Moreover, a functional recovery occurred in MDX skeletal muscle which was probably due to the regeneration of dystrophic muscle.