Decreased expression of extracellular matrix proteins and trophic factors in the amygdala complex of depressed mice after chronic immobilization stress.
BACKGROUND
The amygdala plays an essential role in controlling emotional behaviors and has numerous connections to other brain regions. The functional role of the amygdala has been highlighted by various studies of stress-induced behavioral changes. Here we investigated gene expression changes in the amygdala in the chronic immobilization stress (CIS)-induced depression model.


RESULTS
Eight genes were decreased in the amygdala of CIS mice, including genes for neurotrophic factors and extracellular matrix proteins. Among these, osteoglycin, fibromodulin, insulin-like growth factor 2 (Igf2), and insulin-like growth factor binding protein 2 (Igfbp2) were further analyzed for histological expression changes. The expression of osteoglycin and fibromodulin simultaneously decreased in the medial, basolateral, and central amygdala regions. However, Igf2 and Igfbp2 decreased specifically in the central nucleus of the amygdala. Interestingly, this decrease was found only in the amygdala of mice showing higher immobility, but not in mice displaying lower immobility, although the CIS regimen was the same for both groups.


CONCLUSIONS
These results suggest that the responsiveness of the amygdala may play a role in the sensitivity of CIS-induced behavioral changes in mice.
Department of Anatomy and Neurobiology, Gyeongsang National University, Jinju, South Korea.
Soonwoong
S
Jung
Younghyurk
Y
Lee
Gyeongwha
G
Kim
Hyeonwi
H
Son
Dong Hoon
DH
Lee
Gu Seob
GS
Roh
Sang Soo
SS
Kang
Gyeong Jae
GJ
Cho
Wan Sung
WS
Choi
Hyun Joon
HJ
Kim
D000679:Amygdala / Q000378:metabolism*; D000704:Analysis of Variance; D000818:Animals; D003216:Conditioning, Operant / Q000502:physiology; D003863:Depression / Q000209:etiology / Q000473:pathology*; D004195:Disease Models, Animal; D015536:Down-Regulation / Q000502:physiology*; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism*; D000071235:Fibromodulin; D005518:Food Preferences / Q000502:physiology; D020869:Gene Expression Profiling; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000378:metabolism; D007335:Insulin-Like Growth Factor II / Q000235:genetics / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008813:Mice, Inbred ICR; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D011509:Proteoglycans / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012149:Restraint, Physical / Q000009:adverse effects
D016326:Extracellular Matrix Proteins; C000604332:Fmod protein, mouse; C513121:IGF2 protein, mouse; D018971:Insulin-Like Growth Factor Binding Protein 2; D036341:Intercellular Signaling Peptides and Proteins; D009414:Nerve Growth Factors; C512906:Ogn protein, mouse; D011509:Proteoglycans; D012333:RNA, Messenger; D000071235:Fibromodulin; D007335:Insulin-Like Growth Factor II