Abstract: Objective To investigate the effect of advanced oxidation protein products(AOPP)on nitric oxide(NO)production in mouse peritoneal macrophages(MPMs).Methods MPMs were incubated in the absence or presence of lipopolysaccharide(LPS)with AOPP-modified bovine serum albumin(BSA)prepared by exposure of BSA to hypoclorous acid or pre-treated with AOPP-BSA and subsequent stimulation with LPS.NO production in the supernatants of the culture media was determined spectrophotometrically using Griess method.The cell viability was measured by MTT assay.Results BSA induced significant NO production in MPMs.AOPP modification of BSA significantly inhibited NO production,and AOPP-BSA exhibited time-and dose-dependent inhibition of NO production induced by LPS in MPMs incubated together with LPS or pre-treated before LPS stimulation.Conclusion AOPP-BSA is capable of inhibiting inducible NO production in MPMs.