N-acetylaspartate to total creatine ratio in the hippocampal CA1 sector after transient cerebral ischemia in gerbils: influence of neuronal elements, reactive gliosis, and tissue atrophy.
The authors compared temporal profiles of N-acetylaspartate (NAA) and the NAA/total creatine ratio with neuronal and astrocytic densities and with tissue atrophy in the hippocampal CA1 sector of gerbils after 5-minute bilateral forebrain ischemia and subsequent reperfusion for up to 6 months. The CA1 sector was dissected from 20- micro m lyophilized sections (n = 5) for NAA, phosphocreatine, and creatine assays using high-performance liquid chromatography. Adjacent 10- micro m sections were used for immunohistochemical analysis to follow neuronal and astrocytic responses. The NAA concentration was significantly (P<0.01) decreased after 7 days but leveled off thereafter. The NAA/total creatine (phosphocreatine + creatine) ratio was significantly decreased after 7 days and further decreased (P<0.05) after 6 months. Extensive neuronal damage developed beyond 7 days, while reactive astrogliosis progressed throughout the observation period. There was a good linear correlation (P<0.01) between astroglial density and the NAA/total creatine ratio beyond 7 days. The thickness of the CA1 sector was significantly reduced after 1 month and further reduced after 6 months. Although both NAA level and the NAA/total creatine ratio seemed to be indicators of neuronal damage, the latter could be influenced by reactive astrogliosis with progression of tissue atrophy.
Konaka
Kuni
K
Department of Neurology, Osaka University Graduate School of Medicine, Osaka, Japan.
Ueda
Hirokazu
H
Li
Ji-Yao
JY
Matsumoto
Masayasu
M
Sakoda
Saburo
S
Yanagihara
Takehiko
T
D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism*; D001253:Astrocytes / Q000378:metabolism / Q000473:pathology; D001284:Atrophy; D002452:Cell Count; D017074:Common Variable Immunodeficiency; D003401:Creatine / Q000378:metabolism*; D005849:Gerbillinae; D005911:Gliosis / Q000378:metabolism* / Q000473:pathology; D006624:Hippocampus / Q000378:metabolism* / Q000473:pathology; D002546:Ischemic Attack, Transient / Q000378:metabolism* / Q000473:pathology; D008297:Male; D009474:Neurons / Q000378:metabolism / Q000473:pathology; D015427:Reperfusion Injury / Q000378:metabolism / Q000473:pathology
D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine