title: Resistance Training Alters the Proportion of Skeletal Muscle Fibers but Not Brain Neurotrophic Factors in Young Adult Rats.
abstract: Antonio-Santos, J, Ferreira, DJS, Gomes Costa, GL, Matos, RJB, Toscano, AE, Manhães-de-Castro, R, and Leandro, CG. Resistance training alters the proportion of skeletal muscle fibers but not brain neurotrophic factors in young adult rats. J Strength Cond Res 30(12): 3531-3538, 2016-Resistance training (RT) is related to improved muscular strength and power output. Different programs of RT for rats have been developed, but peripheral and central response has not been evaluated directly in the same animal. To test the hypothesis that RT induces central and peripheral adaptations, this study evaluated the effects of a RT on the performance of a weekly maximum overload test, fiber-type typology, and brain neurotrophic factors in young adult rats. Thirty-one male Wistar rats (65 ± 5 days) were divided in 2 groups: nontrained (NT, n = 13) and trained (T, n = 18). Trained group was submitted to a program of RT ladder climbing, gradually added mass, 5 days per week during 8 weeks at 80% of individual maximum overload. This test was weekly performed to adjust the individual load throughout the weeks for both groups. After 48 hours from the last session of exercise, soleus and extensor digital longus (EDL) muscles were removed for myofibrillar ATPase staining analysis. Spinal cord, motor cortex, and cerebellum were removed for RT-PCR analysis of BDNF and insulin-like growth factor-1 (IGF-1) gene expression. In EDL muscle, T animals showed an increase in the proportion of type IIb fibers and a reduction of type IIa fibers. Insulin-like growth factor-1 gene expression was reduced in the cerebellum of T animals (NT: 1.025 ± 0.12; T: 0.57 ± 0.11). Our data showed that 8 weeks of RT were enough to increase maximum overload capacity and the proportion of glycolytic muscle fibers, but there were no associations with the expression of growth neurotrophic factors.
authors.affiliation: 1Department of Physical Education and Sport Science, Academic Center of Vitoria de Santo Antao, Federal University of Pernambuco, Recife, Brazil;2Department of Nursing, Academic Center of Vitoria de Santo Antao, Federal University of Pernambuco, Recife, Brazil; and3Department of Nutrition, Federal University of Pernambuco, Recife, Brazil.
authors.forename: José
authors.initials: J
authors.lastname: Antonio-Santos
authors.forename: Diórginis José S
authors.initials: DJ
authors.lastname: Ferreira
authors.forename: Gizelle L
authors.initials: GL
authors.lastname: Gomes Costa
authors.forename: Rhowena Jane B
authors.initials: RJ
authors.lastname: Matos
authors.forename: Ana E
authors.initials: AE
authors.lastname: Toscano
authors.forename: Raul
authors.initials: R
authors.lastname: Manhães-de-Castro
authors.forename: Carol G
authors.initials: CG
authors.lastname: Leandro
mesh_terms: D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000473:pathology*; D010805:Physical Conditioning, Animal; D051381:Rats; D017208:Rats, Wistar
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D007334:Insulin-Like Growth Factor I