title: Postnatal training of 129/Sv mice confirms the long-term influence of early exercising on the motor properties of mice.
abstract: A previous study showed that motor experiences during critical periods of development durably affect the motor properties of adult C57BL/6J mice. However, dependence on early environmental features may vary with the genetic profile. To evaluate the contribution of the genetic background on external influences to motricity, we performed the same experiment in a 129/Sv mouse strain that show a strongly different motor profile. Mice were subjected to endurance training (enriched environment or forced treadmill), hypergravity (chronic centrifugation), or simulated microgravity (hindlimb unloading) between postnatal days 10 and 30. They were then returned to standard housing until testing at the age of nine months. The endurance-trained mice showed a fast-slow shift in the deep zone of the tibialis. In addition, mice reared in the enriched environment showed a modified gait and body posture, and improved performance on the rotarod, whereas forced treadmill training did not affect motor output. Hypergravity induced a fast-slow shift in the superficial zone of the tibialis, with no consequence on motor output. Hindlimb unloading provoked an increased percentage of immature hybrid fibres in the tibialis and a shift in the soleus muscle. When compared with similarly reared C57BL/6J mice, 129/Sv mice showed qualitative differences attributable to the lower efficiency of early training due to their lower basal motor activity level. Nevertheless, the results are essentially consistent in both strains, and support the hypothesis that early motor experience influences the muscle phenotype and motor output.
authors.affiliation: Burke Medical Research Institute, Circuit Repair Laboratory, 785 Mamaroneck Ave, White Plains, NY 10605, United States.
authors.forename: Najet
authors.initials: N
authors.lastname: Serradj
authors.affiliation: INSERM U1106, Faculté de Médecine de la Timone, 27 Boulevard Jean Moulin, 13385 Marseille Cedex 05, France. Electronic address: marc.jamon@univmed.fr.
authors.forename: Marc
authors.initials: M
authors.lastname: Jamon
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D005260:Female; D005684:Gait / Q000502:physiology; D006614:Hindlimb / Q000166:cytology / Q000254:growth & development / Q000502:physiology; D006799:Housing, Animal; D018471:Hypergravity; D018472:Hypogravity; D007150:Immunohistochemistry; D008297:Male; D057507:Mice, 129 Strain; D008810:Mice, Inbred C57BL; D009043:Motor Activity / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000166:cytology / Q000254:growth & development* / Q000502:physiology*; D010805:Physical Conditioning, Animal / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology; D011897:Random Allocation; D045442:Rotarod Performance Test; D013045:Species Specificity
keywords: Development; Exercise; Locomotion; Motor behaviour; Mouse models