Quantitative histology and MGF gene expression in rats following SSC exercise in vivo.
Med Sci Sports Exerc
; 38(3): 463-71, 2006 Mar.
Article
em En
| MEDLINE
| ID: mdl-16540833
ABSTRACT
PURPOSE:
We investigated the effects of muscle length during stretch-shortening cycles (SSC) in vivo on changes in MGF gene expression and quantitative morphometry in rat skeletal muscle.METHODS:
Dorsiflexor muscles of male Sprague-Dawley rats were exposed to seven sets of 10 SSC at 500 degrees .s(-1). Animals were randomly assigned to a long muscle length injury group (L-inj), short muscle length injury group (S-inj), or isometric group (Iso), with recoveries examined at 6 or 48 h post-injury for each group. Following exposure, animals were euthanized, and the tissue was prepared for either histology (quantitative morphometry) or RNA isolation, followed by quantitative real-time reverse transcriptase polymerase chain reaction. mRNA levels were measured for mechano-growth factor (MGF), while 18S ribosomal RNA served as the internal reference sample.RESULTS:
Stereological measures indicative of edema and myofiber degeneration were significantly increased in the L-inj SSC group at 48 h when compared with the S-inj or Iso group. MGF mRNA was increased transiently at 6 h in the isometric group. In contrast, MGF mRNA was increased at 48 h in the S-inj, but was not increased at either time point in the L-inj group.CONCLUSION:
These data strongly indicate that exposure to SSC at longer muscle lengths result in greater morphometric indices of inflammation and degeneration than SSC conducted at a shorter muscle lengths or isometric contractions, at the same time that the adaptation to SSC was prolonged and, apparently, not resolved in the L-inj group that was manifested by the lack of up-regulation in MGF mRNA.
Buscar no Google
Base de dados:
MEDLINE
Assunto principal:
Expressão Gênica
/
Contração Isométrica
/
Sistema Musculoesquelético
Limite:
Animals
País/Região como assunto:
America do norte
Idioma:
En
Ano de publicação:
2006
Tipo de documento:
Article