OBJECTIVETo investigate the effect of interleukin-1beta (IL-1beta) on expression and activity of matrix metalloproteinase-2 (MMP-2) of cultured human cardiac fibroblasts and related signaling pathway.

METHODSPrimary human cardiac fibroblasts seeded in 6-well tissue culture plates and cultured to 80% to 90% confluence were harvested at passage 3 to 6 and exposed to IL-1beta at various concentrations for 24 h, culture supernatant and cell protein were obtained. MMP-2 mRNA was determined by RT-PCR. The activity of MMP-2 was analyzed by zymography and the expression of inducible nitric oxide synthase (iNOS) protein level was detected by Western blot analysis. Assessment of NO production in the culture supernatant was performed using the Griess method.

RESULTSIL-1beta (4 ng/ml) significantly increased MMP-2 activity of cultured fibroblasts in a time-dependent manner. MMP-2 mRNA expression was significantly upregulated by IL-1beta (4 ng/ml and 10 ng/ml, all P<0.01). Moreover, IL-1beta also significantly increased NO production in supernatant (P<0.01) and these effects could be significantly blocked by cotreatment with L-NMMA (10(-3) mol/L, all P<0.01). Western blot analysis showed that iNOS could not be detected in unstimulated human cardiac fibroblasts but could be detected in cardiac fibroblasts exposed to IL-1beta.

CONCLUSIONIL-1beta increased MMP-2 activity and transcription of human cardiac fibroblasts via iNOS-NO pathway.