Effect of nitric oxide on phagocytic activity of lipopolysaccharide‐induced macrophages: Possible role of exogenous l‐arginine

Abstract

Among the antimicrobial mechanisms associated with macrophages, NO produced by iNOS plays a major role in intracellular killing, but the relationship between NO and phagocytic activity after injection of inflammatory agents into the peritoneal cavity is not clear. The aim of the present study was to investigate the effect of nitric oxide (NO) on macrophage function after treatment with intraperitoneal lipopolysaccharide (LPS) and the role of exogenous L-arginine administration in this event. Six experimental groups and one control group, each consisting of seven Wistar rats were used: Group I: Control; Group II: LPS; Group III: LPS+L-arginine; Group IV: LPS+L-arginine+Aminoguanidine; Group V: LPS+Aminoguanidine; Group VI: L-arginine; Group VII: Aminoguanidine. Macrophage phagocytic activity and total plasma nitrite levels were increased in the LPS group. In the LPS+L-arginine group, both the phagocytic activity and total plasma nitrite levels showed large increases. Administration of aminoguanidine (AG), a specific iNOS inhibitor, abolished macrophage phagocytic activity and total plasma nitrite levels in the LPS and LPS+L-arginine groups. As a result, we showed that NO produced by macrophages has a role not only in intracellular killing, but also in phagocytic activity.

Stimulation of Unprimed Macrophages with Immune Complexes Triggers a Low Output of Nitric Oxide by Calcium-dependent Neuronal Nitric-oxide Synthase

“…For A and C, nuclei were stained with DAPI, whereas internalized fluorescent beads appear green. Scale bar represents 25 m. iNOS-derived (27,37). Our study is the first to show that nNOS is a major contributor to pro-phagocytic NO.…”

In vitro and in vivo interaction of macrophages from vaccinated and non-vaccinated channel catfish (Ictalurus punctatus) to Edwardsiella ictaluri

“…Following bacterial engulfment by phagocytic cells, resulting events include encounter of pathogens with phagosomal enzymes and other factors aimed at killing the internalized microbes. Among the well characterized phagosomal lethal mechanisms include the reactive oxygen species (ROS) [36,26], the nitrogen intermediates such as nitric oxide [18,51] and other toxic molecules [52]. In this study we observed that macrophages from vaccinated catfish produced higher amount of ROS and nitric oxide compared to macrophages from non-vaccinated fish.…”

Impaired Phagocytosis of Apoptotic Cells by Macrophages in Chronic Granulomatous Disease Is Reversed by IFN-γ in a Nitric Oxide-Dependent Manner

“…Furthermore, NO production itself has been associated with enhanced phagocytosis by LPS-stimulated Mϕs (44). We proposed that IFN-γ–driven enhancement of phagocytosis was mediated by NO.…”