| Autor: |
Astolfi RS; Departamento de Patologia, Faculdade de Medicina, Universidade de São Paulo, Universidade de São Paulo, Av. Dr. Enéas Carvalho Aguiar 470, 05403-000 São Paulo, SP, Brazil., Khouri DG, Brandizzi LI, Avila-Campos MJ, Andrade HF Jr |
| Jazyk: |
angličtina |
| Zdroj: |
Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas [Braz J Med Biol Res] 2007 Mar; Vol. 40 (3), pp. 317-22. |
| DOI: |
10.1590/s0100-879x2007000300006 |
| Abstrakt: |
Sepsis, the leading cause of death in intensive care units, is associated with overproduction of nitric oxide (NO) due to inducible NO synthase (iNOS), responsible for some of the pathologic changes. Aminoguanidine (AG) is a selective iNOS inhibitor with reported inconsistent actions in sepsis. To investigate the influence of iNOS, we studied models of acute bacterial sepsis using acute challenges with aerobic (Escherichia coli) and anaerobic (Bacteroides fragilis) bacteria in the presence of AG. Six-week-old, 23 g, male and female BALB/c and C57Bl/6j mice, in equal proportions, were inoculated (ip) with bacteria in groups of 4 animals for each dose and each experiment in the absence or presence of AG (50 mg/kg, ip, starting 24 h before challenge and daily until day 6) and serum nitrate was measured by chemiluminescence. Both types of bacteria were lethal to mice, with an LD50 of 6 nephelometric units (U) for E. coli and 8 U for B. fragilis. Nitrate production peaked on the second day after E. coli inoculation with 8 and 6 U (P < 0.05), but was absent after non-lethal lower doses. After challenge with B. fragilis this early peak occurred at all tested doses after 24 h, including non-lethal ones (P < 0.05). AG-treated mice challenged with E. coli presented higher survival (P < 0.05) and increased LD50. AG-treated mice challenged with B. fragilis had lower LD50 and higher mortality. Control AG-treated animals presented no toxic effects. The opposite effect of iNOS blockade by AG in these models could be explained by restriction of oxygen for immune cells or an efficient action of NO in anaerobic localized infections. The antagonic role of NO production observed in our bacterial models could explain the reported discrepancy of NO action in sepsis. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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