Alterações da matriz extracelular do fígado, baço e linfonodoscervicais de cães naturalmente infectados com Leishmania (Leishmania)chagasi

Abstract

The aim of this work was study the extracellular matrix alterations in liver, spleen and cervical lymph nodes in dogs naturally infected with Leishmania (Leishmania) chagasi correlating with clinical aspects, histological, parasitological and immunological. This study was carried out with 30 dogs, divided at three groups: ten not infected animals (group control) and twenty infected animals. All them was mongrel dogs with undefined age, obtained from the municipality of Belo Horizonte, MG, metropolitan area. Infected animals were divided in two groups: asymptomatic group composed by ten animals without clinical signs of the disease; group denominated symptomatic: composed by ten animals with classical clinical signals of the disease as skin lesions (alopecia, eczemas and ulcers), loss weight and lymphopathy. During necropsy, spleen, liver and cervical lymph nodes fragments were collected and fixed in buffer formaldehyde solution to 10% for histological analyses. Paraffined sections of the tissues were stained by Hematoxylin-Eosin (HE); Gomori's Ammoniacal Silver staining for reticular fibers and strepto-avidin peroxidase Immunohistochemical method for tissue Leishmania amastigotes detection. Frozen tissue sections of organs were stained by strepto-avidin peroxidase Immunohistochemical method for laminin (LN) tissue characterization and immunofluorescence technique for fibronectina (FN). The tissue images were transferred to a computer video screen by means of the software KS300 and relayed to a computer-assisted image analysis system (Kontron Elektronic/Carl Zeiss, Germany) for morphometrical analysis. Significant increase collagens deposition in liver, spleen and cervical lymph nodes of infected dogs when compared to controls animals. There was significant difference between symptomatic and asymptomatic dogs collagen deposition in organs. Positive correlation between the parasite load and collagen deposition in liver, spleen and cervical lymph nodes of infected animals. In fact, symptomatic animals showed increase collagen deposition in these organs, its can be associate to parasite burden. Adhesive fibers LN and FN expression in liver, spleen and cervical lymph nodes was higher in symptomatic animals than in asymptomatic. No significant statistical difference when we compare LN expression in the spleen and cervical lymph nodes between symptomatic and asymptomatic groups. While in all organs studied of infected animals FN expression demonstrated significant differences in these groups. Our results demonstrate that in canine visceral leishmaniasis induces fibrogenesis in liver, spleen and lymph nodes attached the parasite load and degenerative processes