GFAP and depressive disorder: To explore these issues, an unbiased stereological technique was used to study the total number of astrocytes, and immunofluorescence was used to study the density of bromodeoxyuridine (BrdU)+/glial fibrillary acid protein (GFAP)+ cells in each of three hippocampal subregions (the CA1 region, CA2/3 region, and DG) in a chronic unpredictable stress (CUS) rat model of depression.