The effect of antibacterial agents on the production of nitric oxide induced by lipopolysaccharide in mice

Some antibacterial agents have been shown to neutralize the biological properties of bacterial lipopolysaccharide (LPS). The aim of this study was to eluci- date the role of gentamicin, tobramycin, imipenem, tigecycline, and isoniazid in affecting the production of nitric oxide (NO) induced by LPS in mice. Groups of mice were injected intraperitoneally with LPS alone, antibacterial agent alone, or LPS in combination with an antibacterial agent. Serum NO levels were determined at 1, 3, 6 and 9 hours post-injection using the Griess reagent method. Thin layer chroma- tography was performed to determine if antibacterial agent—LPS interaction had occurred. All the antibacterial agents suppressed NO production. More- over, LPS-induced production of NO was suppressed by all the antibacterial agents, tobramycin and tigecycline being the most effective at 9 hours post-injection. Blocking of any of the stages leading to NO production by the antibacterial agents is suggested. Moreover, thin layer chromatograms obtained are suggestive of LPS-antibacterial agent interactions.