Altered expression of amyloid precursors proteins after traumatic brain injury in rats: in situ hybridization and immunohistochemical study.
The expression of alternatively spliced mRNAs for amyloid precursor protein (APP) isoforms and their translation products were examined in the rat cerebral cortex 1, 3, 6, and 12 h and 1, 3, and 7 days (n = 4-5 in each group) after fluid-percussion brain injury. In situ hybridization studies demonstrated that the expression of APP695 mRNA decreased in and around the damaged area of the cerebral cortex exposed to fluid-percussion injury 1 h after the insult. On the other hand, APP751/770 mRNAs were increased in the regions surrounding the damaged cortical areas 1 day after the injury. An increase of immunoreactive APP was detected in the regions around the damaged cortical areas 3 h after traumatic injury and maintained for the following 3 days. The APP immunoreactivity in the damaged cortices declined to the level of sham-operated animals by post-experimental day 7. Using an anti-amyloid beta (Abeta) protein (17-24) antibody, no deposits of immunoreactive Abeta (17-24) were observed in any of the samples examined in these experiments. These results suggest that the induction of Kunitz-type protease inhibitor (KPI) domain-containing APP mRNAs and the increased accumulation of APP are involved in the physiological and neuropathological responses of brains under various neurodegenerative conditions, including head trauma.
Masumura
M
M
BF Research Institute, c/o National Cardiovascular Center, Osaka, Japan. masumura@silver.ocn.ne.jp
Hata
R
R
Uramoto
H
H
Murayama
N
N
Ohno
T
T
Sawada
T
T
D017398:Alternative Splicing; D016564:Amyloid beta-Protein Precursor / Q000032:analysis / Q000235:genetics*; D000818:Animals; D001930:Brain Injuries / Q000378:metabolism* / Q000473:pathology; D002540:Cerebral Cortex / Q000378:metabolism* / Q000473:pathology; D005786:Gene Expression Regulation; D007150:Immunohistochemistry; D017403:In Situ Hybridization / Q000379:methods; D008297:Male; D014176:Protein Biosynthesis; D020033:Protein Isoforms / Q000032:analysis / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014158:Transcription, Genetic
D016564:Amyloid beta-Protein Precursor; D020033:Protein Isoforms; D012333:RNA, Messenger