Differential influences of microglia on astroglial reactivity

Reactive astrocytes and activated microglia appear acutely following insult to the brain. Following neurologic insult, microglia transform into an activated state, are recruited to the site of injury, and release numerous factors, some of which are believed to contribute to the structural and functional consequences of brain damage. Among the secretory products of activated microglia are cytokines, which regulate the function of various cell types including astrocytes, and cytotoxins, which are proposed to account for the progressive loss of both neurons and astrocytes after injury to the brain. The relationship that exists between neurons and glial cells is critical for the development and proper functioning of neurons. Therefore, any alterations in the normal functioning of astrocytes and microglia may lead to neuronal dysfunction. The objective of the present study was to determine the direct and indirect effects of activated microglia on astrocytes, as measured by the expression of glial fibrillary acidic protein (GFAP), a marker of reactive astrogliosis. (Abstract shortened by UMI.)...