HISTOLOGY AND HISTOPATHOLOGY

From Cell Biology to Tissue Engineering

 

Leishmania amazonensis isolated from human visceral leishmaniasis: histopathological analysis and parasitological burden in different inbred mice

Celeste da Silva Freitas de Souza1, Kátia da Silva Calabrese1, Ana Lúcia Abreu-Silva2, Luiz Otávio Pereira Carvalho1, Flávia de Oliveira Cardoso1, Maria Elizabeth Moraes Cavalheiros Dorval3, Elisa Teruya Oshiro3, Patrícia Flávia Quaresma4, Célia Maria Ferreira Gontijo4, Raquel da Silva Pacheco5, Maria Isabel Doria Rossi6, Sylvio Celso Gonçalves da Costa1 and Tânia Zaverucha do Valle1

1Laboratory of Immunomodulation and Protozoology, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, 2Department of Pathology, University of Maranhão, São Luís, MA, 3Department of Pathology, Center of Biological Science and Health, Federal University of Mato Grosso do Sul, Campo Grande, MT, 4Leishmaniasis Study Group, René Rachou Research Center, FIOCRUZ, Belo Horizonte, MG, 5Laboratory of Clinical Research and Leishmaniasis Control, National Institute of Infectology, FIOCRUZ and 6Laboratory of Cellular Biology Applied to Medicine, Bioengeneers Program, ICB, Federal University of Rio de Janeiro, Rio de Janeiro, Brasil

Offprint requests to: Tânia Zaverucha do Valle, Laboratório de Imunomodulação e Protozoologia, Instituto Oswaldo Cruz, FIOCRUZ, Av. Brasil, 4635 - Pavilhão Carlos Chagas, CEP: 21040-900, Rio de Janeiro - RJ, Brazil. e-mail: taniazv@ioc.fiocruz.br


Summary. Leishmania amazonensis is a major etiological agent of human cutaneous leishmaniasis in the Americas; nevertheless there are some reports of this species causing visceral disease in dogs and men. In the present work we have studied a Leishmania strain isolated from a human case of visceral leishmaniasis. We have infected different mouse strains and analyzed the development of the disease, studying the parasite's ability to visceralize and whether this ability is influenced by host genetics. Female BALB/c, C57BL/6, C57BL/10, CBA, DBA/2, and C3H/He mice were subcutaneously infected with 104 L. amazonensis amastigotes. BALB/c, C57BL/6 and C57BL/10 mice were found to be very susceptible to infection, showing lesions that developed to necrosis and ulceration. CBA mice developed a late but severe lesion. DBA/2 mice developed only discrete lesions, while C3H/He mice did not develop any lesions. All mouse strains except C3H/He showed some degree of visceralization, presenting parasites in the spleen, while BALB/c, C57BL/6 and CBA presented parasites also in the liver. Moreover, most of the strains presented high parasite load at the infection site, whereas DBA and C3H/He mice showed low or no parasite load 90 days after infection, respectively. Histopathology corroborates the results, showing that susceptible mice presented an inflammatory reaction with parasites in the skin, lymph nodes and spleen, while strains that are more resistant presented low parasitism and discrete inflammatory reaction. Results indicate that this isolate is extremely virulent, can easily visceralize and that the pathogenesis of leishmaniasis is, at least in part, related to the genetic background of the host. Histol Histopathol 33, 705-716 (2018)

Key words: Leishmania amazonensis, Visceralization, Histopathological analysis, Susceptibility/resistance, Murine model

DOI: 10.14670/HH-11-965