| dc.identifier | ROMÃO, Raquel P. Ribeiro et al. Comparative evaluation of lesion developmente, tissue damage, and cytokine expression in golden hamsters (Mesocricetus auratus) infected by Inocula with different Leishmania (Viannia) braziliensis concentrations. Infect. Immun., v.82, n.12, p.5203-5213, 2014. | |
| dc.description | 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 104, 105, or 106 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 104 parasites presented nodular lesions, while those
infected with 106 parasites often exhibited ulcerated lesions. The differences in the final lesion sizes were observed between 104
and 105 inocula or 104 and 106 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 104 parasites, while
extensive tissue damage and parasite spleen visceralization occurred with 105 and 106 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. | |
