Hemocytes of the Australian Red Claw Crayfish (Cherax quadricarinatus): Morphology and Hemogram.

The aim of this work was to conduct a morphological analysis of hemocytes of the Australian red claw crayfish (Cherax quadricarinatus). Hemocytes were studied in the native and anticoagulant-treated hemolymph and stained with May–Grünwald and Romanowsky stains. Hemolymph was collected with a syringe from the ventral sinus. Microscopy was carried out using 40× or 100× objective lenses. Hemocyte count and the percentage of each of their types were determined in the Goryaev chamber. In the hemolymph of C. quadricarinatus, among the already known types of hemocytes (agranulocytes or hyalinocytes, semigranulocytes, and granulocytes), we found the cells morphologically different from the previously described, transparent cells. Hyalinocytes are oval or fusiform cells, about 26.6 µm long and 9.2 µm wide. As a rule, they lack granules, but sometimes a small number of tiny granules, sized less than 0.5 µm, can be found. Cells of this type are able to outlive other cells on a slide after isolation. Semigranulocytes are also oval or fusiform cells, 26.7 µm long and 9.3 µm wide, with a moderate number of small-sized granules (<0.5 µm) and sparse medium-sized granules ranging from 0.77 to 1.69 µm. Granulocytes are oval-shaped cells, the largest of all types, having a length and width of 28.7 and 11.1 µm, respectively. They contain large (0.8–2.48 µm) numerous granules and show a high refraction, due to which this cell type is well recognizable under a microscope. These cells have a lowest nuclear–cytoplasmic ratio compared to the former two types. Transparent cells are specifically characterized by abundant well-developed pseudopodia. After cell rounding, its diameter averages 10.7 ± 1.11 µm. This cell type begins to show up 10 min after their isolation in the anticoagulant-untreated hemolymph. Hyalinocytes are the dominant type of cells in the hemolymph, their proportion is 48.3 ± 11.4%, while semigranulocytes and granulocytes account for 26.3 ± 7.8 and 25.2 ± 6.9%, respectively. The total number of hemocytes varies in a wide range from 820 to 5510 cell/µL, with the average number of cells being 2707 ± 1096 cell/µL. The proportion of transparent cells averages 18.2 ± 3.8%. [ABSTRACT FROM AUTHOR]