Production of H 2 O 2 and NO by rat peritoneal macrophages in response to gut commensal bacteria

Abstract

The importance of commensal bacteria in the immune system development and its involvement in the etiopatogenetic mechanisms of complex multifactorial and multigenic diseases is well documented. The aim of the present study was to compare the levels of hydrogen peroxide (H2O2) and nitric oxide (NO) produced by resident peritoneal macrophages from the autoimmune disease susceptible Dark Agouti (DA) rats vs. resistant Albino Oxford (AO) rat strain, under basal conditions and subsequent to in vitro stimulation with gut commensals. Following the stimulation with phorbol myristil acetate (PMA), E. coli/PMA or P. mirabilis/PMA, AO rats macrophages have produced significantly higher levels of H2O2 compared to the cells from DA rats. Strain differences in NO production were not detected under basal conditions and after the stimulation with lipopolysaccharide and P. mirabilis. However, after the in vitro stimulation with E. coli, AO rats macrophages have produced higher levels of NO compared to DA rats macrophages. Our results demonstrated that macrophages from AO rats have higher potential to produce H2O2 and NO in response to specific commensal bacteria when compared to DA rats. A possible relationship between the macrophage activity in response to commensal bacteria and the susceptibility to induction of autoimmune/inflammatory diseases in AO and DA rat strains is suggested.