OBJECTIVETo investigate the pathogenicity of matrix metalloproteinase 8, 9 (MMP-8, MMP-9) regulations of polymorphonuclear leukocytes (PMNs) by challenge of Porphyromonas gingivalis (P. gingivalis) with different fimA genotypes.

METHODSThe studies mainly adopt the isopycnic sedimentation separation to separate the PMNs from human peripheral blood. P. gingivalis ATCC 33277 (type I), WCSP 115 (type II), WCSP 1.5 (type III), W83 (type IV), WCSP 559 (type IV) were assessed for their inductions of MMP-8, MMP-9 expression in PMNs. MMP-8, MMP-9 protein levels in culture supernatant were determined by ELISA at different time intervals (5 min, 30 min, 1 h, 2 h) following continuous co-culture of bacteria with PMNs.

RESULTSMMP-8 and MMP-9 protein levels produced by PMNs co-culture with the I fimA-IV fimA P. gingivalis were significantly stronger than unsimulated group. The velocity and quantity of MMP-8 produced by PMNs co-culture with the II fimA P. gingivalis and IV fimA P. gingivalis were more than III fimA, IVfimA P. gingivalis. The MMP-9 protein levels produced by PMNs co-culture with the I fimA, II fimA, IV fimA P. gingivalis was significantly stronger than III fimA and IV fimA P. gingivalis.

CONCLUSIONII fimA and IV fimA P. gingivalis have stronger pathogenicity relatively, which indicate that fimA genotype is associated with pathogenesis of P. gingivalis.