AIM: To investigate mechanism of bradykinin(BK)on inflammations of retinal pigment epithelium(RPE)cells.

METHODS: ARPE-19 cells were cultured in vitro, stimulated by 100nM BK for 24h. Cell morphology changes were observed by microscope, and BK receptor localization was detected through cell immunofluorescence. Changes of Ca²⁺ in BK and BR antagonist stimuli were detected by laser scanning confocal microscopy. The expressions of COX-1, COX-2, eNOS and iNOS protein in control group and BK group were detected by Western Blot.

RESULTS: After the stimulation of BK, there was no significant changes of ARPE-19 cells in morphology. Kinin B1 receptors(B1R)and B2 receptors(B2R)could be detected in ARPE-19 cells. Compared with control group, Ca²⁺ concentrations significantly increased in BK group; in B1R antagonist group and B2R antagonist group Ca²⁺ concentrations increased less than BK group; B1R and B2R antagonist group showed no obvious changes in Ca²⁺ concentrations. Compared with control group, COX-2 and iNOS protein concentrations were significantly increased in BK group(P<0.001).

CONCLUSION: BK induces the increasing expression of COX-2 and iNOS in the cultured ARPE cells through binding with either B1R or B2R.