RESUMO
Angiostrongylus costaricensis can infect several mollusks, and its migration route in intermediate hosts has been studied only in Sarasinula marginata. To verify the susceptibility of Omalonyx sp. as an intermediate host of A. costaricensis and to analyze the nematode migration route, individuals were infected with stage 1 larvae. Obtained stage 3 larvae were orally inoculated in mice, and after 30 days, adult worms and stage 1 larvae were recovered, demonstrating Omalonyx susceptibility and suitability to infection. To define the parasite migration routes, specimens of Omalonyx with 30 min, 1 h, 2 h, 4 h, 6 h, 8 h, 2 days, 5 days, 10 days, 12 days, 15 days, 20 days, 21 days, 25 days, 28 days, and 30 days of infection were fixed and serially sectioned. Histological sections were stained with hematoxylin-eosin. The results were compared to those described in S. marginata. Oral and cutaneous infections were noted. After the penetration, larvae were retained, mainly in the fibromuscular tissue, by hemocytes, or they spread to the whole organism through the circulation, following the anatomical structure of the vasculature. The perilarval hemocyte reaction in Omalonyx was more intense until stage 2 larva instar, decreasing in the presence of stage 3 larvae. Differences in some aspects of hemocyte reaction between S. marginata and Omalonyx exemplify interspecific peculiarities in snail response to the same parasite.
Assuntos
Angiostrongylus/fisiologia , Angiostrongylus/patogenicidade , Gastrópodes/parasitologia , Interações Hospedeiro-Parasita , Infecções por Strongylida/patologia , Angiostrongylus/crescimento & desenvolvimento , Animais , Feminino , Trato Gastrointestinal/parasitologia , Hemócitos/parasitologia , Larva/patogenicidade , Larva/fisiologia , Masculino , Camundongos , Pele/parasitologia , Infecções por Strongylida/parasitologiaRESUMO
We characterized herein the microarchitecture of the equine thymus along with post-natal development (6 months-->18 years). Thymuses showed an involutional process, beginning before the puberty and defined by five histological grades, which consider the progressive cortical thymocyte depletion, shrinkage and rearrangement of the epithelial network and increase in extracellular matrix (ECM). A second feature of the equine thymus was the presence of eosinopoiesis, erythropoiesis, mastocytopoiesis and plasmacytogenesis. Additionally, lymphatic vessels, full of lymphocytes, were particularly prominent. Distribution of ECM proteins was heterogeneous, being denser in the medulla, as well as basement membranes of capsule, septa and perivascular spaces, thus similar to the patterns seen in other mammals. In vitro, horse thymic nurse cells produce ECM proteins, which are relevant in thymocyte/epithelial cell interactions. In conclusion, the equine thymus presents morphological and involutional characteristics similar to other mammals, exhibiting particular features, as prominent non-lymphoid hematopoiesis and lymphatic vessels.
Assuntos
Timo/anatomia & histologia , Animais , Anticorpos/farmacologia , Adesão Celular/efeitos dos fármacos , Adesão Celular/fisiologia , Colágeno Tipo IV/análise , Eosinófilos/citologia , Células Epiteliais/citologia , Células Epiteliais/fisiologia , Epitélio/anatomia & histologia , Epitélio/fisiologia , Matriz Extracelular/química , Matriz Extracelular/fisiologia , Feminino , Fibronectinas/análise , Fibronectinas/fisiologia , Cavalos , Imuno-Histoquímica , Laminina/análise , Laminina/fisiologia , Vasos Linfáticos/anatomia & histologia , Vasos Linfáticos/citologia , Linfócitos/citologia , Masculino , Mastócitos/citologia , Microscopia Eletrônica , Microscopia de Fluorescência , Timo/química , Timo/ultraestruturaRESUMO
The intermediate hosts of Angiostrongylus costaricensis are terrestrian molluscs, mostly of the family Veronicellidae. The present work aimed at clarifying more accurately the sites of penetration and the migratory routes of A. costaricensis in the tissue slugs and at verifying the pattern of the perilarval reaction at different times of infection. Slugs were individually infected with 5,000 L1, and killed from 30 min to 30 days after infection. From 30 min up to 2 hr after infection, L1 were found within the lumen of different segments of the digestive tube having their number diminished in more advanced times after exposition until complete disappearance. After 30 min of exposition, percutaneous infection occurred, simultaneously to oral infection. Perilarval reaction was observed from 2 hr of infection around larvae in fibromuscular layer, appearing later (after 6 hr) around larvae located in the viscera. A pre-granulomatous reaction was characterized by gradative concentration of amebocytes around larvae, evolving two well-organized granulomas. In this work we confirmed the simultaneous occurrence of oral and percutaneous infections. Perilarval reaction, when very well developed, defined typical granulomatous structure, including epithelioid cell transformation. The infection also caused a systemic mobilization of amebocytes and provoked amebocyte-endothelium interactions