Immunoperoxidase study of astrocytic reaction in Junin virus encephalomyelitis of mice

Abstract

Intracerebral inoculation of strain XJ Clon 3 of Junín virus into 1-2-day-old mice resulted in the appearance of viral antigen, detectable by means of the peroxidase antiperoxidase (PAP) technique, within the cytoplasm of the neurons of the cerebral cortex, the basal nuclei, cerebellum, pons, medulla, spinal cord, and spinal ganglia; Junín antigen was likewise observed, although to a lesser extent, in the cytoplasm of astrocytes. The viral antigen was found in highest concentration at the cytoplasmic periphery, near the cell membrane, where complete virions are formed by budding. In some cells a "tigroid" distribution of the antigen was observed, suggestive of its production and concentration within the granular endoplasmic reticulum. In spite of the heavy infection of the neural structures, the neurons did not always show major alterations. By immunolabeling of the glial fibrillary acidic protein (GFAP) by the PAP method, a severe glial response could be seen in infected mice, featuring hyperplasia, hypertrophy, and shape distortion of the astrocytes. This easy labeling was not observed in normal mice of the same age, and suggests the accelerated maturation of the astrocytes and the increased GFAP synthesis by direct action of the virus upon such cells. In view of its specificity, use of the PAP technique for GFAP immunolabeling will most likely replace the traditional metal impregnation methods in the study of the astrocytes. Its utilization would be indicated whenever astroglial changes are suspected in any CNS pathologic condition.

Melatonin Inhibits β-Adrenoceptor-Stimulated Cyclic AMP Accumulation in Rat Astroglial Cell Cultures

“…Primary rat brain cultures are considered suitable models of untransformed astroglial cells, and are used increasingly for neurobiological studies [28,33], In every case, the previ ous characterization of the cell types which are present in the monolayer is needed: in our hands, the immunolabeliing of GFAP allows a positive identification of the astroglial cells, both in vivo [14] and in vitro [2], The cultures utilized in the present study consisted of predominantly immature cells, whose astroglial nature was confirmed by keeping similar monolayers in culture for longertimes, to allow full develop ment of the cells ( fig. 1,2).…”

Junin virus‐induced astrocytosis is impaired by iNOS inhibition

“…Although Junin virus (JV)-induced experimental encephalitis of mice [Lascano and Berría, 1983] and rats [Lascano et al, 1989] is characterized by marked astrogliosis disclosed by glial fibrillary acidic protein (GFAP) labeling, such overwhelming astrocyte activation fails to correspond with the slight morphological changes in viral antigen-laden neurons and the mildness of inflammatory reaction. Therefore, it was of interest to resort to the mouse model to investigate whether there is increased expression of iNOS and, if so, to determine the effects of its specific inhibition by using amino guanidine (AG) [Griffiths et al, 1993].…”

Astrogliosis in the cerebral cortex of gerbils after long-term exposure to 1,1,1-trichloroethane.

“…Wallerian degeneration of the optic nerve has been shown to induce an increased GFA protein content in the damaged nerve (10). Spinal cord transections (2,3) and cryogenic lesions of the brain (1), as well as viral and experimental allergic encephalomyelitis (28,47), are also known to induce formation of fibrils in the astrocytes of damaged tissue. In human neuropathology, the demonstration of astrogliosis is considered indisputable evidence of abnormality in the central nervous system.…”