Localization of metallothioneins-I & -II and -III in the brain of aged dog.
Localization of metallothionein (MT) -I & -II and MT-III and its significance in the brain aging in dogs were examined using immunohistological and molecular pathological techniques. MT-I & -II immunohistochemistry showed positive staining in the hypertrophic astrocytes throughout the aged dog brains; these MT-I & -II immunoreactive astrocytes were predominant in the cerebral cortex and around the blood vessels in the brain. These findings dominated in the brain regions with severe age-related morphological changes. In situ hybridization using MT-I mRNA riboprobes also demonstrated signals for MT-I mRNA in these hypertrophic astrocytes. Immunohistochemistry using a guinea pig antiserum against a synthetic polypeptide of canine MT-III demonstrated positive MT-III immunoreactivity predominantly in neurons in the Zn-rich regions such as hippocampus and parahippocampus. The findings were supported by in situ hybridization using MT-III mRNA riboprobes. Both MT-III immunoreactivity and signals for MT-III mRNA were demonstrated in neurons in the brain regardless of the intensity of the age-related changes. These results suggest, first, MT-I & -II may be induced in relation to the progress of the age-related morphological changes in the brain, playing an important role in the protection of the brain tissue from the toxic insults responsible for the brain aging, and second, MT-III may play a role in maintenance of Zn-related essential functions of the brain.
Kojima
S
S
Department of Veterinary Pathology, Tottori University, Japan.
Shimada
A
A
Morita
T
T
Yamano
Y
Y
Umemura
T
T
D000375:Aging / Q000502:physiology*; D000818:Animals; D015153:Blotting, Western / Q000662:veterinary; D001923:Brain Chemistry; D004285:Dogs / Q000502:physiology*; D005260:Female; D017403:In Situ Hybridization / Q000662:veterinary; D008297:Male; D008668:Metallothionein / Q000032:analysis* / Q000235:genetics; D000090023:Metallothionein 3; D009419:Nerve Tissue Proteins / Q000032:analysis* / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis
D000090023:Metallothionein 3; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D008668:Metallothionein