Investigation of changes in global gene expression in the frontal cortex of early-weaned and socially isolated piglets using microarray and quantitative real-time RT-PCR.
We hypothesize that early-weaned piglets experience aberrant expression of stress-responsive genes in the frontal cortex, a key brain area involved in cognitive function and behavior organization. To test this hypothesis, female early-weaned piglets (EW; n = 6) were weaned 10 days after birth, while non-weaned piglets (NW; n = 6) were left with their dams. Half of EW (n = 3) and NW (n = 3) animals were socially isolated (SI) for 15 min at 12 days of age, when all animals (n = 12) were euthanized and tissue collected. The effects of EW and SI were examined by gene expression profiling using cDNA microarray hybridizations, generated from a porcine brain cDNA library. A total of 103 genes were differentially expressed (P < 0.05, fold change >1.25) among four direct comparisons. Forty-two genes had known functions, from which 24 showed relevant brain-related functions. Quantitative real-time polymerase chain reaction (Q-RT-PCR) was used to confirm regulation of expression of a subset of 6 genes with important brain functions, selected from the microarray outcomes. In non-weaned animals, a significant suppression of mRNA abundance for carboxypeptidase E, 14-3-3 protein and phosphoprotein enriched in astrocytes 15 kDa was observed in response to SI. Also, in early-weaned animals, diazepam binding inhibitor and actin-related protein 2/3 complex mRNA levels were suppressed in response to SI. Results suggest that social isolation of non- and early-weaned piglets may impact expression of genes involved in regulation of neuronal function, development, and protection in the frontal cortex of young pigs.
Poletto
R
R
Animal Behavior and Welfare Group, Department of Animal Science, Michigan State University, 1287 Anthony Hall, East Lansing, MI 48824, USA.
Siegford
J M
JM
Steibel
J P
JP
Coussens
P M
PM
Zanella
A J
AJ
D000818:Animals; D018076:DNA, Complementary / Q000096:biosynthesis / Q000235:genetics; D005260:Female; D015870:Gene Expression / Q000502:physiology*; D020411:Oligonucleotide Array Sequence Analysis; D017397:Prefrontal Cortex / Q000502:physiology*; D012313:RNA / Q000096:biosynthesis / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012934:Social Isolation; D013315:Stress, Psychological / Q000235:genetics / Q000523:psychology; D013552:Swine; D014886:Weaning
D018076:DNA, Complementary; D012313:RNA