Skunk musk causes methemoglobin and Heinz body formation in vitro

Abstract

BACKGROUND: A captive Red Panda developed a regenerative anemia with Heinz bodies after being sprayed by a skunk. A definite cause-and-effect relationship between skunk musk and oxidative erythrocyte damage has not been reported, but it was suspected in one reported case of a dog with Heinz body hemolytic anemia. OBJECTIVE: The objective was to determine whether skunk musk induces oxidative HGB damage in vitro. METHODS: Plasma and RBC were harvested from heparinized blood of 3 dogs, 3 cats, and a Red Panda. Skunk musk was solubilized in ethanol and mixed with plasma from each species to make stock solutions of 4% musk and 4% ethanol. Aliquots of RBC were resuspended in autologous stock solutions and solvent controls to yield musk concentrations of 0%, 0.04%, and 0.4% (by volume). Aliquots were incubated at 37°C for 4-72 hours and assessed for oxidative damage by visual inspection, optical absorbance spectroscopy, transmission electron microscopy, and light microscopy after Wright and vital New Methylene Blue staining. RESULTS: Dose-dependent brown color and absorption changes characteristic of methemoglobin were present by 4 hours and increased over 24 hours (Red Panda) and 72 hours (dog and cat). Similarly, there were time-dependent (all species) and dose-dependent (dog and cat) increases in the number of Heinz bodies, which were present by 4 hours and numerous by 24 hours. CONCLUSIONS: In vitro, skunk musk causes Heinz body and methemoglobin formation in canine, feline, and Red Panda RBC, supporting the clinical association between Heinz body hemolytic anemia and skunk spray exposure.