Cytochemical Staining Characteristics, Morphology, and Ultrastructural Features of Peripheral Blood Cells From One Captive Blue Iguana ( Cyclura lewisi )

ABSTRACT Background The Grand Cayman blue iguana ( Cyclura lewisi ) is an endangered species of lizard endemic to Grand Cayman Island. The cytochemical staining characteristics, cell morphometrics, and ultrastructure have not been reported for blood from this species. Objectives The objectives for this blue iguana blood cell study were to perform routine and cytochemical staining, document morphometric measurements, and identify structures using bright‐field (BF), differential interference contrast (DIC), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Methods Opportunistic blood samples were collected from one captive adult male blue iguana housed at the Milwaukee County Zoo, Milwaukee, WI, USA, during three routine health exams. CBCs, biochemistry panels, cytochemical staining (leukocyte acid phosphatase AcP with and without tartrate, alkaline phosphatase ALP, alpha‐naphthyl acetate esterase ANAE, leukocyte peroxidase LEP, periodic acid‐Schiff PAS, Sudan black B SBB, and Toluidine blue TB) were performed. Results CBCs and biochemistry panel results were within range for a healthy captive adult male blue iguana. The cytochemical reactions were determined. The basophils, erythrocytes, heterophils, monocytes, and thrombocytes reacted positively to PAS. Only the heterophils had positive reactions to ALP, SBB, and LEP. Basophils were positive to TB. Monocytes and thrombocytes stained positive for AcP. Red blood cell cytoplasmic inclusions held stain with ANAE, AcP, PAS, and TB. The morphology and ultrastructure of blue iguana blood cells were documented using BF, DIC, SEM, and TEM. Conclusion All of the microscopic and staining methods allowed for improved differentiation of cell types and characteristics. The results may serve as a reference for any study of blood cells in other reptile species.