Ocular experimental leishmaniasis in C57BL/10 and BALB/c mice induced by Leishmania amazonensis infection

AbstractThere are few studies on human ocular leishmaniasis found in the literature. The purpose of this study was to describe experimental ocular leishmaniasis, caused by Leishmania amazonensis evaluating two different infection routes: intravitreal and instillation in C57BL/10 and BALB/c mice. In this work all animals presented low anti-Leishmania IgM and IgG titers regardless of the infection route or mouse strain. The histopathological eye analysis showed that the mice inoculated by the intravitreal route developed more severe lesions, presenting parasites in the anterior region of the eye 60days after infection. The C57BL/10 mice presented cells containing parasitophorous vacuoles associated with pigmented cells and inflammatory infiltrate, which included mast cells. Ninety days after infection no parasites could be found in either mouse strain, which led us to hypothesize that parasites had been eliminated. In this context, we show that both intravitreal and instillation routes were effective in promoting ocular leishmaniasis infections in C57BL/10 and BALB/c mice. There were no differences in the parasite infection between the two mouse models and it mimicked the ocular lesions described in symptomatic dogs in endemic areas of visceral leishmaniasis

Biological behavior of Leishmania (L.) amazonensis isolated from a human diffuse cutaneous leishmaniasis in inbred strains of mice

After a subcutaneous injection of 104 purified amastigotes of an isolate from a diffuse case of cutaneous leishmaniasis caused by the MHOM/BR/76/Ma-5 strain of Leishmania amazonensis, three inbred mouse strains developed a progressive nodular lesion, which evolved to an ulcerated lesion. Based on these data, mice of BALB/c, C57BL/6 or C57BL/10 could be classified as susceptible. The majority of mice developed metastases in the footpads, ear, tail, nose and oral mucosa. Amputation of the members related to the primary lesion was frequent. Experiments using the limiting dilution analysis showed that there was no correlation between lesion and parasite load. It has been demonstrated that these mouse strains could be considered excellent models for mucocutaneous leishmaniasis when infected with L. amazonensis. Metastatic lesions caused destruction of the nasal region with many parasitized macrophages under the epithelial surface of the nasal mucosa. Bone destruction occurred with an extensive inflammatory reaction presenting macrophages heavily parasitized by amastigotes. The parasites also spread to the periodontal ligament and other structures of the oral cavity, which could induce a severe inflammatory process. This study indicates that both nasal and oral lesions in mice infected by L. amazonensis were characterized by an inflammatory reaction with the presence of a high parasite load within macrophages

Influência do manejo da palhada de capim-braquiária (Brachiaria decumbens) sobre o desenvolvimento inicial de soja (Glycine max) e amendoim-bravo (Euphorbia heterophylla) Influence of straw management of Brachiaria decumbens on the initial development of Glycine max and Euphorbia heterophylla

Com o objetivo de avaliar os efeitos de diferentes manejos de palhada de capim-braquiária sobre o desenvolvimento inicial da cultura de soja e da planta daninha amendoimbravo, foi conduzido um experimento em condições de casa de vegetação no NuPAMFCA/UNESP, BotucatuSP. Os tratamentos utilizados foram: manejo da palhada na superfície do solo + irrigação superficial (T1); manejo da palhada na superfície do solo + irrigação subsuperficial (T2); palhada incorporada ao solo (T3); e testemunha sem cobertura (T4). A palhada foi colhida no campo 30 dias após dessecação com o herbicida glyphosate (1,44 g i.a. ha-1). O delineamento experimental utilizado foi o inteiramente casualizado, com sete repetições, sendo as unidades experimentais vasos plásticos, com a soja e o amendoim-bravo semeados paralelamente, em linhas distintas. O T1 reduziu significativamente o índice de velocidade de germinação (IVG) e a altura das plântulas de soja aos 5 e 10 dias após a emergência (DAE), ao contrário do amendoim-bravo, o qual não sofreu interferência dos tratamentos estudados, constituindo-se em uma planta-problema para sistemas produtivos com palhada de capim-braquiária. Os resultados da análise de crescimento (TCA - taxa de crescimento absoluto, TCR - taxa de crescimento relativo e TAL - taxa de assimilação líquida) das plântulas de soja e amendoim-bravo apresentaram valores máximos aos 15 DAE, com exceção do T3 para soja, o qual reduziu expressivamente o desenvolvimento em relação aos demais tratamentos.<br>An experiment was carried out under greenhouse conditions at NuPAM-FCA/UNESP, Botucatu, SP, Brazil to evaluate the effects of different types of straw management of Brachiaria decumbens on the initial development of Glycine max and Euphorbia heterophylla. The treatments were: straw on soil surface + irrigation on the top (T1); straw on soil surface + underirrigation (T2); straw incorporated into the soil (T3) and control (T4). B. decumbens straw was collected in the field thirty days after glyphosate application (1.44 g i.a. ha-1). The experimental design was completely randomized with seven replications, with the experimental units consisting of plastic pots, where G. max and E.heterophylla were sown in parallel lines. T1 reduced significantly the germination speed index (GSI) and G. max plant height at 5 and 10 days after emergence (DAE) while E. heterophylla did not suffer interference of the treatments, being a problem for cropping systems involving B. decumbens straw. Growth analysis data (AGR - absolute growth rate, RGR - relative grotw rate and NAR - net assimilation rate) on G. max and E. heterophylla presented maximum values at 15 DAE, except for T3 with G. max, which presented expressive decrease in its initial development, compared to the other treatments