Hematologic reference intervals for Xenopus tropicalis with partial use of automatic counting methods and reliability of long‐term stored samples

Abstract

We provide hematologic RI for X tropicalis, suggest how automated cell counts may facilitate hematologic assessments of frogs, and establish that blood in Natt-Herrick solution is stable 2 years post collection.

Hematologic reference intervals for Rana sylvatica (Lithobates sylvaticus) and effect of infection with Frog Virus 3 (Ranavirus sp., Iridoviridae)

“…Based on our rather conservative cell classification and identification, blood cells in Wood Frogs include erythrocytes, thrombocytes, lymphocytes, monocytes, neutrophils, eosinophils, and basophils. Neutrophils often contain small structures resembling mammalian Döhle bodies, also reported in healthy African Clawed and Australian Tree Frogs . We found no evidence of granulocytes that resembled heterophils, which have rod‐shaped orange–pink granules and have been reported in some amphibian species .…”

“…Red blood cell‐related variables of Wood Frogs were compared to reported values for other frog species (Table and Figure ). While the relative cell count represented by the RBC was similar in all frog species, and PCV and RBC counts in Wood Frogs were similar to those of Northern Leopard Frogs, they were lower than those of Australian Tree Frogs ( Litoria caerulea and L infrafrenata ) and African Clawed Frogs ( X tropicalis and X laevis ) …”

“…Erythrocytes of Wood Frogs, as in other amphibians, were oval with moderate amounts of pink cytoplasm and a central ovoid densely purple nucleus often with irregular margins (Figure ). The size of Wood Frog erythrocytes was similar to those of Northern Leopard Frogs, Rana pipens , and larger than those of African Clawed Frogs ( Xenopus laevis ), African Tropical Clawed Frogs ( X tropicalis ), Common Green Tree Frogs ( Litoria caerulea ), and White‐Lipped Tree Frogs ( Litoria infrafrenata ) (Table and Figure ) …”

“…The mixture was refrigerated (4°C) and 19 months later, hemocytometer and automated cell counts were performed. As previously documented, only mild to negligible cellular deterioration occurred during storage time . The numbers of RBC, WBC, and thrombocytes were calculated by hemocytometry using a light microscope and following a slightly modified standard methodology .…”

“…Both grids on the hemocytometer were counted and the average was calculated. Although the discrepancy between WBC counts from the 2 grids was sometimes > 15%, the counting procedure was not repeated . Calculation of the concentration of each cell type per liter of blood was done using the following formulas adapted from published protocols:…”