metallothionein and Cerebral-Infarction

To study the neurophysiological functions of metallothioneins (MTs), localization of MT-I and -II was examined immunohistochemically in a variety of brain lesions in dogs, including infarct, laminar cortical necrosis, hemorrhage, invasive growth of tumour, inflammatory lesions in granulomatous meningoencephalitis and distemper encephalitis. MT-I and -II were demonstrated in both nucleus and cytoplasm of hypertrophic astrocytes in most brain lesions examined regardless of the type, size, localization and duration of the lesions. In addition, MT expression was stronger in a population of hypertrophic astrocytes localizing inside of the surviving brain tissue rather than those localizing at the boundary between the surviving brain tissue and necrotic area, where severe inflammatory changes were developing. These results suggest that MT-I and -II may play roles not only in protection of neurons from metals and free radicals ubiquitous in the inflammatory lesions but also in repair of injured neural tissues.

Topics: Adenocarcinoma; Animals; Astrocytes; Brain Diseases; Brain Neoplasms; Cerebral Hemorrhage; Cerebral Infarction; Distemper; Dog Diseases; Dogs; Encephalitis, Viral; Female; Glial Fibrillary Acidic Protein; Hypertrophy; Inflammation; Male; Meningoencephalitis; Metallothionein; Necrosis; Neoplasm Invasiveness; Pituitary Neoplasms

The metallothioneins in vitro are both effective free radical and transitional metal ion scavengers. For this reason we investigated the expression of this protein in the normal CNS and after ischaemia using a monoclonal anti-metallothionein antibody to metallothionein isoforms I and II. Using immunohistochemistry and confocal laser scanning microscopy, we found anti-GFAP and anti-metallothionein were co-localized in astrocytes at the edges of infarcts. Energy dispersive X-ray microanalysis demonstrated high levels of copper and iron in the metallothionein positive reactive astrocytes. On the basis of the in vitro properties of these proteins, the functional importance of metallothionein in reactive astrocytes could be as a free radical scavenger and metal ion chelator.

Topics: Aged; Aged, 80 and over; Antibodies, Monoclonal; Astrocytes; Brain Ischemia; Cerebral Infarction; Electron Probe Microanalysis; Fluorescent Antibody Technique, Direct; Glial Fibrillary Acidic Protein; Humans; Immunoenzyme Techniques; Immunohistochemistry; Isomerism; Metallothionein; Microscopy, Confocal; Middle Aged