Glial fibrillary acidic protein (GFAP) is the most important marker of astrocytes, that are the major glial cells in the nervous tissue and exhibit receptors to several steroid hormones, which have an apparent influence in their genic expression. The aim of this study was to evaluate if dexamethasone (DX) administration in therapeutic protocols to dogs would be capable of affecting the astrocytic expression of the protein. Samples from the pons and the spinal cord of dogs, treated (n=6) or not (n=6) with DX, were submitted to GFAP immunohistochemical staining and astrocytic reactivity was determined by colorimetry in a computer system for image analysis. Difference statistically significant was noted for the mean areas stained with GFAP in the pons of dogs treated and non-treated with DX, as well as in the spinal cord of dogs which previously received or not DX, with clear tendency of drug-induced reduction in the astrocyte expression of this protein. GFAP expression in the spinal cord was greater than in the pons, regardless the use of DX or not.
astrocytes; corticoid; dexamethasone; dogs; GFAP; immunohistochemistry
