Age-related changes in expression of metallothionein-III in rat brain.
Metallothionein (MT)-III is a metal binding protein, called growth inhibitory factor, and is mainly expressed in the central nervous system. Since MT-III decreases in the brain of Alzheimer's disease (AD), a growing interest has been focused on its relationship to neurodegenerative diseases. To clarify age-related changes in the MT-III expression and its inducibility against oxidative stress, we analyzed the expression of MT-III and its mRNA in the brain of lipopolysaccharide (LPS)-treated aged rats. In the frontal cortex, basal expression of MT-III mRNA was significantly increased with aging, while it was observed no induction of MT-III mRNA against LPS administration in the aged rat brain. MT-III immunopositive cells were increased in the frontal, parietal and piriform cortices, hypothalamus and amygdaloid nucleus with aging. The LPS treatment induced MT-III expression in the brain of young-adult rats, but not in the aged rat brain. Furthermore, the MT-III induction with LPS treatment was mainly observed in oligodendrocyte and microglia. In the present study, we showed that inducibility of brain MT-III against oxidative stress may be reduced with aging. Since it has been reported that MT-III has neuroprotective roles as an antioxidant, present results suggest that MT-III is closely related to the neurodegeneration in the aged animals.
Department of Brain Science, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikatacho, Okayama 700-8558, Japan. miyazaki@cc.okayama-u.ac.jp
Ikuko
I
Miyazaki
Masato
M
Asanuma
Youichirou
Y
Higashi
Chiharu Aoki
CA
Sogawa
Ken-ichi
K
Tanaka
Norio
N
Ogawa
D000375:Aging / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D007150:Immunohistochemistry; D008070:Lipopolysaccharides / Q000494:pharmacology; D000090023:Metallothionein 3; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009457:Neuroglia / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344
D008070:Lipopolysaccharides; D000090023:Metallothionein 3; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger