Morphological examination of protein inclusions in stranded cetaceans

Abstract

Introduction: This paper reports on the presence, morphology and nature of intracytoplasmic eosinophilic globules in the hepatocytes of cetaceans stranded in the Canary Islands. Materials and Methods: Liver samples from 115 cetaceans of 17 different species were formalin fixed and paraffin embedded. In samples presenting globules, histochemical and immunohistochemical techniques were used to detect glycoproteins using Periodic acid-Schiff with diastase treatment (PASd), and specific proteins: alpha-1-antitrypsine (A1AT) and fibrinogen (FB). An ultrastructural study of the globules was also performed. Results: In 95 out of 115 (82.6%) liver specimens, intracytoplasmic hyaline eosinophilic globules were observed in hepatocytes; different results were obtained for PASd, A1AT and FB staining, and ultrastructural morphology also differed. Conclusion: Intracytoplasmic protein inclusions (hyaline globules) are present in a range of inflammatory and cardiovascular disorders in stranded cetaceans. Further research is required in terrestrial mammals to compare morphological findings with those reported here for stranded cetaceans.