Mast cells in the dog skin: Distribution, density, heterogeneity and influence of fixation techniques

This study was conducted with the aim of examining the location, the morphology, and numerical distribution of mast cells in the different areas of the healthy adult dog skin. Skin samples taken from the cheek, pinna, thorax and thigh areas of 10 healthy dogs were used as the study material. The results show the existence of mast cell heterogeneity in dog skin with respect to staining with alcian blue / safranin O and formaldehyde fixation sensitivity. Mast cells characterized by four combination of these parameters were observed: Mast cells containing only alcian blue-positive granules which were formalin-sensitive, mast cells containing only alcian blue-positive granules which were formalin-resistant, mast cells containing only safranin O-positive granules which were formalin resistant and mast cells containing a mixture of alcian blue-positive and safranin O-positive granules which were formalin resistant. With toluidine blue staining method, it was founded that IFAA fixed tissues were contained more mast cells than those tissues fixed with the 10% formaldehyde in all four regions. The difference in average number of mast cells per mm2 between the IFAA and the 10% formaldehyde fixed tissues was statistically significant (p0.05), in the other three areas, statistically significant differences (p