BACKGROUND:It has been demonstrated that curcumin can increase the activities of various anti-oxidase in blood and tissue,effectively eliminate various free radicals,reduce the production of peroxisome,and alleviate oxidative stress reaction.Whether it has the same effect on microglia? OBJECTIVE:To observe the effects of curcumin on the expressions of inducible nitric oxide synthase (iNOS),nuclear factor-κB(YF-κB),and superoxide dismutase (SOD) in microglial cell line BV stimulated by lipopolysaccharide(LPS).DESIGN:An observational comparative study.SETTING:Research Room of Biochemistry,Medical College of Nantong University.MATERIALS:Mice microglia cell line BV,iNOS and NF-κ B reporter gene plasmids were presented by Dr.Bhat.NR.from the Medical University of South Carolina(USA).Curcumin was produced by the Xian Branch of China Chengdu Scholar Bio-Tech.Co.,Ltd.;LPS (E.Coli 026:B6).anti-mice iNOS monoclonal antibody,horseradish peroxidase labeled goat-anti-mice IgG were the products of Sigma Company (USA).METHODS:The experiments were carried out in the Research Room of Biochemistry,Medical College of Nantong University from May 2006 to April 2007.①Detection of iNOS:The cells Were seeded onto 24-well plate at the density of 1*105,After the cells had adhered to the cover glasses,the cells were grouped as negative control group(the primary antibody was replaced by phosphate bufffered solution PBS);normal control group (the cells were normally cultured);LPS-treated group(the cells were treated with LPS for 24 hours);curcumin+LPS group(the cells were treated with curcumin for 1 hour and LPS for 24 hours).The expressions of iNOS protein were detected with immunocytochemical staining.②Detennination of iNOS and NF-κ B gene activities:According to the introduction of the kit for transfection,jNOS or NF-κ B report gene plasmids were transiently transfected with Lipofectamine TM 2000 liposomes into the cells in the 24-well plate for 24 hours.The cells were divided into normal control group(the cells were normally cultured after transfected with report gene plasmids);blank plasmid group (the cells were normally cultured after transfected with blank plasmids);LPS-treated group(thc cells were treated with LPS for 4 hours after transfected with report gene plasmids);curcumin+LPS group (the cells were treated with curcumin for 1 hour and LPS for 24 hours after transfected with report gene plasmids).The content of luciferase in the cell lysis buffer was determined after cell lysis.③Determination of SOD activity:The cells were seeded into culture bottle at the density of 1×106,and the divided into four groups.including normal control group (the cells were normally cultured);LPS-treated group (the cells were treated with LPS for 24 hours);curcumin+LPS group (the cells were treated with curcumin for 1 hour and LPS for 24 hours);vitamin C+LPS group(the cells were treated with vitamin C for 1 hour and LPS for 24 hours).The SOD activity was determined with xanthine oxidase and quantitative colorimetric assay.MAIN OUTCOME MEASURES:The expressions of iNOS protein,iNOS and NF-κB,and the activity of SOD were observed.RESULTS:①Expression of iNOS protein in microglia:The expression of iNOS protein in the LPS-treated group was obviously higher than that in the negative control group(P＜0.01):Those in the curcumin+LPS group were significantly decreased as compared with that in the LPS-treated group(P＜0.01) ②Expressions of iNOS and NF-κB genes:The expressions of iNOS and NF-κ B genes in the LPS-treated group were significantly higher than those in the normal control group(P＜0.0 1);Those in the curcumin+LPS group were significantly lower than those in the LPS-treated group (P＜0.01).③SOD activity:The activity of SOD in the LPS-treated group was significantly lower than those in the normal control group(P＜0.01).It in the curcumin+LPS group and vitamin C+LPS group was significantly higher than that in the LPS-treated group(P＜0.01).CONCLUSION:Curcumin could inhibit the expression of iNOS in the activated microglia.and it also has the abilities in eliminating free radicals and antagonizing lipid peroxidation.