Short-lived killifishes of the genus Nothobranchius Peters, 1868 (Cyprinodontiformes) are considered promising model organisms for biomedical research on ageing and tumorigenesis. We conducted histopathological analysis of 411 adult individuals from three Nothobranchius species to study details on spontaneous age-related neoplastic lesions. Light microscopy based on H&E and toluidine blue-stained sections revealed (a) non-proliferative liver changes with pronounced vacuolation of hepatocytes; (b) proliferation of kidney haemopoietic tissue contributing to excretory system damage; (c) proliferation of splenic mononuclear haemoblasts accompanied by reduced erythropoiesis; (d) proliferation of mononuclear cell aggregates in the liver parenchyma; and (e) rare occurrence of hepatocellular adenomas. Ziehl-Neelsen (ZN) staining revealed that the proliferative lesions are a host defence response to mycobacterial infections manifested by activation of the mononuclear phagocytic system and atypical granulomatous inflammatory reaction. 16S rRNA analysis identified three species of Mycobacterium in our samples. Our findings turn attention to lesions which mimic neoplasms by their gross appearance and question the light microscopic interpretation of lesions unless differential ZN staining is included. Beyond the limitations of our morphological approach, the intensity of mycobacterial infections is a challenging opportunity for research into the molecular-genetic background of the mononuclear phagocytic system reaction in Nothobranchius killifish.

• Klíčová slova
• mononuclear phagocytic system, mycobacterial infections, proliferative lesions, tumour misdiagnosis,
• MeSH
• bakteriální RNA analýza   MeSH
• Cyprinodontiformes * MeSH
• Mycobacteriaceae izolace a purifikace   MeSH
• Mycobacterium marinum izolace a purifikace   MeSH
• mykobakteriózy diagnóza   mikrobiologie   patologie   veterinární   MeSH
• nádory diagnóza   etiologie   patologie   veterinární   MeSH
• nemoci ryb patologie   MeSH
• RNA ribozomální 16S analýza   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• bakteriální RNA MeSH
• RNA ribozomální 16S MeSH