Physiol. Genomics 38: 138-148, 2009.
First published April 21, 2009; doi:10.1152/physiolgenomics.00014.2009
1094-8341/09 $8.00
Received 21 January 2009;
accepted in final form 16 April 2009.
Physiological Genomics 38:138-148 (2009)
1094-8341/09 $8.00 © 2009 American Physiological Society
Expression profiling of skeletal muscle in young bulls treated with steroidal growth promoters
L. Carraro
1,*,
S. Ferraresso
1,*,
B. Cardazzo
1,
C. Romualdi
2,
C. Montesissa
1,
F. Gottardo
3,
T. Patarnello
1,
M. Castagnaro
1 and
L. Bargelloni
1
1 Department of Public Health, Comparative Pathology, and Veterinary Hygiene, University of Padova, Legnaro (PD)
2 CRIBI Biotechnology Centre, Department of Biology, University of Padova, Padova
3 Department of Animal Science, University of Padova, Legnaro (PD), Italy
Dexamethasone (Dex), alone or in association with estrogens, is often illegally administered per os at very low dosage as a growth promoter in beef cattle, with effects that are opposite to the muscle wasting and atrophy induced by repeated administration at therapeutic dosages. In vitro and in vivo studies have investigated the catabolic effects of Dex at therapeutic doses on skeletal muscle, demonstrating an increase in the expression of GDF8 (myostatin) gene, a well-known negative regulator of skeletal muscle mass, in a dose-dependent way. This suggested a direct role of myostatin in Dex-induced muscle wasting. In the present study, an oligonucleotide microarray platform was used to compare expression profiles of beef cattle muscle in animals treated with either Dex or Dex plus 17-β estradiol (Estr) administered at subtherapeutic dosage, against untreated controls. Data analysis demonstrates that the expression profiles were strongly affected by Dex treatment with hundreds of genes upregulated with relevant fold-change, whereas seven genes were downregulated including the myostatin gene. On the contrary, the number of differentially regulated genes was lower in response to the addition of Estr to the Dex treatment. Differentially regulated genes were analyzed to describe the effects of these treatments on muscle physiology, highlighting the importance of specific pathways (e.g., Wnt or cytokine signaling) and cellular processes (e.g., cell shape and motility). Finally, the observed differences in the expression profile will allow the development of indirect bio-markers to detect illegal Dex treatments in beef cattle using quantitative RT-PCR.
microarray; dexamethasone; estradiol; myostatin
Copyright © 2009 by the American Physiological Society.
