Longitudinal analysis of gene expression in porcine skeletal muscle after post-injection local injury.
OBJECTIVE
The purpose of this study is to describe the time course of gene expression in a skeletal muscle local injury induced by an intramuscular (IM) injection, and to compare the dynamics of gene expression with pathological events.


METHODS
Ten piglets received 4 IM injections of propylene glycol in the longissimus dorsi muscles 6 h, 2, 7, and 21 days before euthanasia, where control and injected muscle sites were sampled for RNA isolation and microscopic examination. The hybridization of nylon cDNA microarrays was carried out with radioactive probes obtained from the muscle RNA.


RESULTS
153 genes were found under- or over-expressed at least once among the investigated time-conditions. The eight most discriminant genes were also identified: Two genes (GTP-binding protein RAD and Ankyrin repeat domain protein) were over-expressed at 6 h and six genes between 2 and 21 days (Osteonectin, Fibronectin, Matrix metalloproteinase-2, Collagen alpha 1(I) chain, Collagen alpha 2(I) chain, and Thymosin beta-4). Necrosis, inflammation and regeneration were observed through both the dynamics of gene expression profiles and through the microscopic examinations.


CONCLUSIONS
Our data demonstrate that several pathways are involved in post-injection muscle injury, and that necrosis, inflammation and regeneration are not sequential but occur in parallel.
Ferré
Pierre J
PJ
UMR181 de Physiopathologie et Toxicologie Expérimentales, INRA, ENVT, National Veterinary School, 23 chemin des Capelles, BP 87614, Toulouse cedex 03, 31076, France.
Liaubet
Laurence
L
Concordet
Didier
D
SanCristobal
Magali
M
Uro-Coste
Emmanuelle
E
Tosser-Klopp
Gwenola
G
Bonnet
Agnès
A
Toutain
Pierre-Louis
PL
Hatey
François
F
Lefebvre
Hervé P
HP
D000818:Animals; D003094:Collagen / Q000235:genetics; D024042:Collagen Type I / Q000235:genetics; D000090602:Collagen Type I, alpha 1 Chain; D015536:Down-Regulation / Q000235:genetics; D005353:Fibronectins / Q000235:genetics; D020869:Gene Expression Profiling; D007273:Injections, Intramuscular / Q000009:adverse effects; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000235:genetics; D009124:Muscle Proteins / Q000235:genetics*; D018482:Muscle, Skeletal / Q000293:injuries / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D015676:Osteonectin / Q000235:genetics; D013552:Swine; D013947:Thymosin / Q000235:genetics; D013997:Time Factors; D015854:Up-Regulation / Q000235:genetics; D018631:ras Proteins / Q000235:genetics; D000099201:Thymosin beta(4)
D003094:Collagen; D024042:Collagen Type I; D000090602:Collagen Type I, alpha 1 Chain; D005353:Fibronectins; D020778:Matrix Metalloproteinase 2; D009124:Muscle Proteins; D015676:Osteonectin; D013947:Thymosin; D018631:ras Proteins; D000099201:Thymosin beta(4)