OBJECTIVETo investigate the role of angiotensin II (AngII)-angiotensin II type 1 receptor (AT1R) pathway in the production of proinflammatory cytokines in macrophage, and to analyze its mechanisms.

METHODSRAW264.7 macrophages were cultured in vitro in DMEM nutrient medium containing 10% FBS, and then they were divided into control group (ordinary culture for 6 hours without any stimulation), ZD7155 group (pretreated with 38 µmol/L AT1R-specific inhibitor ZD7155 for 1 hour, then cultured with fresh nutrient solution for 6 hours), AngII group (cultured with 0.01 µmol/L AngII for 6 hours), and ZD7155 + AngII group (pretreated with 38 µmol/L AT1R-specific inhibitor ZD7155 for 1 hour, then cultured with 0.01 µmol/L AngII for 6 hours) according to the random number table. Contents of TNF-α and IL-1β in the supernatant were measured by ELISA. Expressions of TNF-α mRNA and IL-1β mRNA were determined by RT-PCR. Activity of NF-κB and AP-1 were examined by electrophoretic mobility shift assay. Data were processed with one-way analysis of variance.

RESULTSCompared with those in AngII group [(119 ± 14), (105 ± 17) pg/mL, respectively], the levels of TNF-α and IL-1β in the supernatant in control group [(24 ± 11), (24 ± 6) pg/mL, with F value respectively 1.62, 8.03, P values all below 0.01], ZD7155 group [(22 ± 11), (25 ± 8) pg/mL, with F value respectively 1.62, 4.52, P values all below 0.01], and ZD7155 + AngII group [(45 ± 13), (62 ± 11) pg/mL, with F value respectively 1.16, 2.29, P < 0.05 or P < 0.01] were all obviously decreased. The expressions of TNF-α mRNA and IL-1β mRNA, and activity of NF-κB and AP-1 showed the similar changes as above: (1) The levels of TNF-α mRNA and IL-1β mRNA in AngII group were all higher than those in control group (with F value respectively 7.59, 3.38, P < 0.05 or P < 0.01), ZD7155 group (with F value respectively 10.66, 2.24, P values all below 0.05), and ZD7155 + AngII group (with F value respectively 5.10, 5.09, P values all below 0.01). (2) Activity of NF-κB and AP-1 was respectively 69 027 ± 2502, 36 752 ± 2055 in AngII group, all higher than those in control group (45 709 ± 1203, 20 325 ± 2695, with F value respectively 4.32, 1.72, P values all below 0.01), ZD7155 group (46 303 ± 1897, 21 951 ± 2517, with F value respectively 1.74, 1.50, P values all below 0.01), and ZD7155 + AngII group (38 271 ± 690, 22 365 ± 3797, with F value respectively 13.13, 3.41, P values all below 0.01).

CONCLUSIONSAngII can mediate activation of transcription factor NF-κB and AP-1 via combination of AT1R, thereby contributing to the production and release of proinflammatory cytokines TNF-α and IL-1β in macrophage.