Morphological evaluation of canine platelets on Giemsa- and PAS-stained blood smears

Abstract

The morphology of canine platelets (changes in size, shape, staining characteristics, degree of activation and clump formation, distribution of granules, appearance of vacuoles on Giemsa-stained smears) was investigated in 20 healthy control and 181 diseased dogs. In the group of the sick dogs 84 animals suffered from disorders affecting directly the haematological parameters or the haematopoietic organs such as bleeding, thymic haemorrhage, haemolytic disorders, lymphoma, immune-mediated thrombocytopenia, and other 97 dogs were affected by other diseases (hepatopathy, nephropathy, hepatic, splenic or intestinal neoplasm, skin diseases, diabetes mellitus, Cushing's syndrome, sepsis). The alterations found in platelet morphology were not specific for any disorder. The most common platelet abnormalities were polychromasia and the presence of giant platelets. These changes occurred in a high number in disorders accompanied by bleeding or haemolysis. Anisocytosis was the most frequent finding in hepatic, splenic or intestinal neoplasms and in certain endocrinopathies. Microcytosis was observed in immunemediated thrombocytopenia, hepatic neoplasms and endocrine disorders. Extreme platelet activation was common in haemolysis, hepatopathies, neoplastic diseases and sepsis. Vacuolisation was present in thymic haemorrhage, pancreatitis, diabetes mellitus and Cushing's syndrome. A new morphologic phenomenon, i.e. a ring-like formation of granules, was described in the cytoplasm of the platelets both in healthy and diseased animals. In addition, two forms of pathologic granulation were also described for the first time in Giemsa-stained blood smears: the pseudonuclear and the spot-like formation of granules, which were observed especially in disorders affecting the blood cells. The granulation and morphological characteristics of platelets on smears stained by periodic acid-Schiff reaction (PAS) were also studied. Three localisations of granulation were observed, such as peripheral, eccentric and diffuse. The ratio of PAS-positive and -negative platelets was evaluated in several diseases. Our findings support the diagnostic value of platelet evaluation by light microscopy and help clinicians/clinical pathologists to understand why morphologic changes of thrombocytes might be expected in several diseases.

Effectiveness of Two Methods for Preparation of Autologous Platelet-Rich Plasma: An Experimental Study in Rabbits

“…Smears are valid to evaluate many parameters that are indicative of platelet function, such as changes in morphology, size, shape, staining characteristics, degree of activation and clump formation, distribution of granules and appearance of vacuoles. 34 In the present study, the PRP smears of Group II showed some deformed, round-shaped platelets which may indicate premature platelet activation. Premature activation would lead to an early release of growth factors, causing them to move to the top of the tube when centrifuged.…”

Platelet Function and Therapeutic Applications in Dogs: Current Status and Future Prospects

“…Canine platelet structure and anatomy has been characterized by light and electron microscopy techniques; the latter revealed a more detailed internal structure. For instance, light microscopy showed platelet size and shape and the presence of cytoplasmic processes on the surface of activated platelets [12,13]. Electron microscopy illustrated more specific platelet structures [14] such as alpha, dense, and glycogen granules [15,16] (Figure 1).…”

Comparative (quantitative and qualitative) analysis of three different reagents for preparation of platelet-rich plasma for hair rejuvenation

“…Qualitative analysis of smears is used to evaluate various parameters that are indicative of platelet function, such as changes in morphology, size, shape, staining characteristics, degree of activation and clump formation, distribution of granules, and appearance of vacuoles. [ 19 ] In this study, the morphology of platelets was worst in the samples from vials containing EDTA. This may be attributed to the destructive effect of EDTA on platelets.…”