Data/hora: 29/05/2024 02:14:04

Provedor de dados: | Brazilian Journal of Medical and Biological Research
País: | Brazil
Título: | Role of nitric oxide and superoxide in Giardia lamblia killing
Data: | 1997-01-01
Ano: | 1997
Palavras-chave: | Nitric oxide; Macrophage; Peroxynitrite; Giardia lamblia; Cytotoxicity; Superoxide.
Resumo: | Giardia lamblia trophozoites were incubated for 2 h with activated murine macrophages, nitric oxide (NO) donors or a superoxide anion generator (20 mU/ml xanthine oxidase plus 1 mM xanthine). Activated macrophages were cytotoxic to Giardia trophozoites (~60% dead trophozoites). This effect was inhibited (&amp;gt;90%) by an NO synthase inhibitor (200 µM) and unaffected by superoxide dismutase (SOD, 300 U/ml). Giardia trophozoites were killed by the NO donors, S-nitroso-acetyl-penicillamine (SNAP) and sodium nitroprusside (SNP) in a dose-dependent manner (LD50 300 and 50 µM, respectively). A dual NO-superoxide anion donor, 3-morpholino-sydnonimine hydrochloride (SIN-1), did not have a killing effect in concentrations up to 1 mM. However, when SOD (300 U/ml) was added simultaneously with SIN-1 to Giardia, a significant trophozoite-killing effect was observed (~35% dead trophozoites at 1 mM). The mixture of SNAP or SNP with superoxide anion, which yields peroxynitrite, abolished the trophozoite killing induced by NO donors. Authentic peroxynitrite only killed trophozoites at very high concentrations (3 mM). These results indicate that NO accounts for Giardia trophozoite killing and this effect is not mediated by peroxynitrite
Tipo: | Info:eu-repo/semantics/other
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1997000100015
Editor: | Associação Brasileira de Divulgação Científica
Relação: | 10.1590/S0100-879X1997000100015
Formato: | text/html
Fonte: | Brazilian Journal of Medical and Biological Research  v.30 n.1 1997
Fonte: | info:eu-repo/semantics/openAccess