OBJECTIVETo investigate the effect of activated greater omental milky spots and peritoneal macrophages in mice on tumoricidal activity against gastric carcinoma SGC-7901, following intraperitoneal (i.p.) injection of INF-gamma, staphylococcin aureus or NDV-L.

METHODSThe quantitative changes of milky spots were determined by activated carbon, the number of the macrophage in milky spots was assessed by nonspecific esterase stain and the number of peritoneal macrophages was counted by trypan blue exclusion. The morphology of peritoneal macrophages was observed by scanning electron microscope, the amount of TNF-alpha and iNOS mRNA expressed by peritoneal macrophages was measured by fluorescence quantitative PCR and the cytotoxicity of peritoneal macrophages supernatant against SGC-7901 was evaluated by MTT assay.

RESULTSIt was found in the treated groups that: 1. The amount of greater omental milky spots and the macrophages in milky spots increased, 2. The number of peritoneal macrophages increased. The peritoneal macrophages were in activated status. The effect TNF-alpha and iNOS mRNA expression increased and 3. The cytotoxicity against in vitro SGC-7901 increased.

CONCLUSIONIntraperitoneal injection of IFN-gamma, staphylococcin aureus or NDV-L could activate the milky spots of the greater omentum and the macrophages in peritoneal cavity in mice, with IFN-gamma being the best. The supernatant of activated peritoneal macrophages has cytotoxicity against SGC-7901. Administration of LPS to macrophages cultured in vitro could amplify the activation and enhance the cytotoxicity of the supernatant against SGC-7901.