The Effect Of Enterococcus Faecalis On Polymorphonuclear Leukocyte

Objective:After PMNs was triggered by E.faecalis in vitro,the release of MMP-8 and apoptosis rate of polymerpho-nuclear leukocytes (PMNs) were evaluated。Methods:The PMNs were isolated using a modification of the Dextran /Ficoll methods from healthy donors.The activated Enterococcus faecalis suspension was prepared and added to PMNs suspension as experiment group;as a positive control,PMA was used,and as negative control,PMNs suspension was incubated with PBS ,the release of MMP-8 was measured at 0,20,60 and120min after initiation of incubation.Enterococcus faecalis lysate acted on polymorphonuclear leukocytes as experiment group, PMNs suspension was incubated with PBS as negative control,samples in two groups were incubated at 37℃for 2h,5h,10h,15h.The apoptosis rate of PMNs tested by Flow Cytometry.Results:1.At 0minute,Enterococcus faecalis induced a similar MMP-8 release compare with the negative control and positive control, (P>0.01);whereas at 20min, 60min and 120min,Enterococcus faecalis induced a significant lower MMP-8 release compare with the positive control(P<0.01. )2.The apoptosis rate of PMNs tested by Flow Cytometry:Apoptosis rate of PMNs in both groups increased along with time;apoptotic rate in experiment group was higher than that in the control group at 2h,5h,10h,15h (P< 0.01);at 15h, apoptotic index were significantly higher than it of control group(experiment group 70.98±5.27;control group 44.61±3.27;P<0.01).Conclusions:1.After Enterococcus faecalis acting on PMNs,Enterococcus faecalis induced little MMP-8 release from PMNs.2.The result of apoptosis rate indicated that Enterococcus faecalis did not delay PMNs apoptosis.