title: Comparative evaluation of lesion development, tissue damage, and cytokine expression in golden hamsters (Mesocricetus auratus) infected by inocula with different Leishmania (Viannia) braziliensis concentrations.
abstract: The golden hamster (Mesocricetus auratus) is a susceptible model to Leishmania (Viannia) spp.; however, available studies employ different infection protocols, which account for clinical and pathological presentation differences. Herein, L. (V.) braziliensis preparations were standardized to contain 10(4), 10(5), or 10(6) parasites to determine an optimal inoculum that ensured cutaneous lesions without causing a disseminated infection in hamsters. Lesion development was followed for 105 days by size measurements, and skin, draining lymph node, spleen, and sera were investigated to check parasite load, spleen visceralization, cytokine expression, histopathological changes, and anti-Leishmania IgG levels. The lesion emergence time was inversely proportional to the parasite concentration in the inocula. Animals infected by 10(4) parasites presented nodular lesions, while those infected with 10(6) parasites often exhibited ulcerated lesions. The differences in the final lesion sizes were observed between 10(4) and 10(5) inocula or 10(4) and 10(6) inocula. High IFNG expression, anti-Leishmania IgG levels, and parasite load occurred independently of the inoculum used. A mild inflammatory skin involvement was observed in animals infected with 10(4) parasites, while extensive tissue damage and parasite spleen visceralization occurred with 10(5) and 10(6) parasites. These results indicate that inocula with different concentrations of parasites generate differences in the time of lesion emergence, clinical presentation, and systemic commitment, despite high and similar IFNG expression and parasite load. This suggests that a modulation in the immune response to different parasite numbers occurs in an early phase of the infection, which could dictate the establishment and magnitude of the chronic phase of the disease.
authors.affiliation: Laboratório Interdisciplinar de Pesquisas Médicas, Instituto Oswaldo Cruz (FIOCRUZ/RJ), Rio de Janeiro, Brazil.
authors.forename: Raquel P
authors.initials: RP
authors.lastname: Ribeiro-Romão
authors.affiliation: Laboratório de Biologia Molecular e Doenças Endêmicas, Instituto Oswaldo Cruz (FIOCRUZ/RJ), Rio de Janeiro, Brazil.
authors.forename: Otacílio C
authors.initials: OC
authors.lastname: Moreira
authors.affiliation: Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, USA.
authors.forename: Elvia Yaneth
authors.initials: EY
authors.lastname: Osorio
authors.affiliation: Laboratório de Imunoparasitologia, Instituto Oswaldo Cruz (FIOCRUZ/RJ), Rio de Janeiro, Brazil.
authors.forename: Lea
authors.initials: L
authors.lastname: Cysne-Finkelstein
authors.affiliation: Laboratório Interdisciplinar de Pesquisas Médicas, Instituto Oswaldo Cruz (FIOCRUZ/RJ), Rio de Janeiro, Brazil.
authors.forename: Adriano
authors.initials: A
authors.lastname: Gomes-Silva
authors.affiliation: Laboratório Interdisciplinar de Pesquisas Médicas, Instituto Oswaldo Cruz (FIOCRUZ/RJ), Rio de Janeiro, Brazil.
authors.forename: Joanna G
authors.initials: JG
authors.lastname: Valverde
authors.affiliation: Laboratório Interdisciplinar de Pesquisas Médicas, Instituto Oswaldo Cruz (FIOCRUZ/RJ), Rio de Janeiro, Brazil.
authors.forename: Claude
authors.initials: C
authors.lastname: Pirmez
authors.affiliation: Laboratório Interdisciplinar de Pesquisas Médicas, Instituto Oswaldo Cruz (FIOCRUZ/RJ), Rio de Janeiro, Brazil.
authors.forename: Alda Maria
authors.initials: AM
authors.lastname: Da-Cruz
authors.affiliation: Laboratório Interdisciplinar de Pesquisas Médicas, Instituto Oswaldo Cruz (FIOCRUZ/RJ), Rio de Janeiro, Brazil eduardo@ioc.fiocruz.br.
authors.forename: Eduardo Fonseca
authors.initials: EF
authors.lastname: Pinto
mesh_terms: D000825:Animal Structures / Q000469:parasitology / Q000473:pathology; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D016207:Cytokines / Q000032:analysis*; D004195:Disease Models, Animal; D005260:Female; D006651:Histocytochemistry; D007074:Immunoglobulin G / Q000097:blood; D007892:Leishmania braziliensis / Q000276:immunology*; D016773:Leishmaniasis, Cutaneous / Q000276:immunology* / Q000469:parasitology / Q000473:pathology*; D008198:Lymph Nodes / Q000469:parasitology / Q000473:pathology; D008647:Mesocricetus; D059208:Parasite Load; D012867:Skin / Q000469:parasitology / Q000473:pathology*; D013154:Spleen / Q000469:parasitology / Q000473:pathology; D013997:Time Factors
chemical_list: D000913:Antibodies, Protozoan; D016207:Cytokines; D007074:Immunoglobulin G