Efeitos da hipoxia e do oxigenio hiperbarico nos modelos in vitro e in vivo da leishmaniose

AUTOR(ES)

Wagner Welber Arrais da Silva

DATA DE PUBLICAÇÃO

2003

RESUMO

Infections can cause the formation of hypoxic areas (low PO2). The altered blood flow, isquemia, cell proliferation and the presence of microorganisms causes hypoxia in injured tissues. Macrophages adapt to the presence of hypoxia and alter their metabolism, pro-inflammatory lymphokines production and phagocytosis activity. Lesions induced by Leishmania amazonensis are characterized by a large number of amastigotes, inflammatory cells migration, secondary infection with anaerobic and aerobic bacteria and altered tissue blood flow which can cause chronic areas of hypoxia. We have analyzed the effect of hypoxia on L. amazonensis in vitro and in vivo models and also studied the effect of hyperbaric therapy on murine leishmaniasis. The murine 1774 macrophages cultures infected with L. amazonensis amastigotes under hypoxic conditions (5% Oz) showed a decrease in the number of infected cells compared with cell cultures infected in normoxia (21% O2). However macrophage cultures activated with gamma-interferon and bacterial lipopolisaccharides showed the same percentage of infected cells compared with non stimulated macrophages in hypoxia and, no significant nitrite production. Hyperbaric treatment inhibited the growth and differentiation of L. amazonensis promastigotes and amastigotes. In addition BALB/c mice infected with L. amazonensis and treated with hyperbaric therapy (1 hour/day, 2.5 ATA, 100% O2) showed a significant decrease of lesions size. We also observed a decreased of the edematous process, an improvement of local blood flow, and early metastasis. Taken together our results provided evidences that hypoxia is an important stimulator/activator factor for L. amazonensis killing macrophages and also that hyperbaric therapy can be tested as an adjuvant therapy with anti-leishmanial drugs

ASSUNTO(S)

macrofagos leishmaniose - brasil

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