Effects of three inhibitors of nitric oxide synthase on host resistance to bacterial infection

To examine the effects of three nitric oxide synthase inhibitors on survival in a murine sepsis model. Design: Prospective randomized experimental trials. Setting: Prospective randomized experimental trials. Setting: Laboratory. Subjects: Female Balb/c mice. Interventions: Escherichia coli (10(8) colony-forming-units/body) were injected into the peritoneal cavities of Balb/c mice. N-G-nitro-L-arginine-methyl-ester, N-G-monomethyl-L-arginine, or N-iminoethyl-L-ornithine was given at various concentrations, intraperitoneally, one hour before bacterial challenge. Measurements: One hundred and fifteen animals were observed for survival. Results: These inhibitors provided the mice no protection from the bacterial challenge. Notably, pretreatment with N-G-nitro-L-arginine-Methyl-ester (100 mg/kg i.p.) actually reduced survival time after E. coli challenge. Conclusions: Inhibition of nitric oxide production improved neither the survival time nor rate in this murine sepsis model.