Morphological Features and Morphometric Parameters of Eosinophils in Peripheral Blood of the Raccoon Dog Nyctereutes procyonoides (Grey, 1834)

Abstract

This work was aimed at analyzing the features of the morphology and morphometric parameters of eosinophils and their granules in the raccoon dog Nyctereutes procyonoides (Grey, 1834). Pappenheim staining of blood smears was used to determine white-blood-cell count and to assess the features of the morphology and morphometric parameters of eosinophils and their granules. Cytochemical methods were used to determine localization of cationic proteins, as well as eosinophilic peroxidase in eosinophils. ANOVA was used to assess gender effects. The study has shown that raccoon dogs are characterized by a high relative content of eosinophils (7–10% of the total population of white blood cells), as well as by the presence of large secretory granules in them. In addition to eosinophils with the typically rich cytoplasmic granularity, larger cells containing secretory granules in minor quantities and, in some cases, vacuole-like granules were present in blood smears. Gender effects manifested themselves in the higher proportion of eosinophils with a low level of cytoplasmic granularity in males compared to females, while females showed higher values of morphometric parameters (the number and mean area of granules in a single cell, as well as the ratio of the area taken by granules to the cell area). Since the causes of the appearance of eosinophils with a low content of granules, as well as with vacuolization of the cytoplasm, in raccoon dogs are not quite clear, this problem needs further investigation.