The Astrocyte Response in Experimental Portalsystemic Encephalopathy: An Electron Microscopic Study

Abstract

The ultrastructural features of Alzheimer type II astrocytes are described in an experimental model of hepatic encephalopathy. Encephalopathy was produced in rats by constructing a portacaval shunt followed by gavage feedings of an ammoniated cation exchange resin. There was hyperplasia and hypertrophy of astrocytes in the cerebral cortex. By electron microscopy the astrocytes exhibited an expanded cytoplasmic compartment associated with proliferation of mitochondria and endoplasmic reticulum. Some astrocytes in addition displayed increased cytoplasmic electron-lucency and vacuolar changes. The implication of these alterations for the role of astrocytes in the pathogenesis of hepatic coma is discussed.