溶血与非溶血型粪肠球菌对大鼠再感染根尖周炎炎症进程的影响

Effect of Cytolysin of Enterococcus Faecalis on the Inflammatory Progress of Rat Reinfected Periapical Periodontitis

目的：比较分析不同基因型（溶血型与非溶血型）粪肠球菌致大鼠再感染根尖周炎炎症程度及TNF-α表达差异。方法：将SD大鼠双侧上颌第一磨牙开髓暴露3周,形成口腔常驻混合菌（不含粪肠球菌）感染的慢性根尖周炎后分为4组：消毒组（根管预备、消毒后观察2周）;慢性根尖周炎组（继续观察8周）;溶血型及非溶血型粪肠球菌再感染根尖周炎组（根管消毒2周后分别注入溶血型与非溶血型粪肠球菌,观察1、2、3、4、5、6周）。通过HE和免疫组化染色进行各观察时间点的组织病理学及肿瘤坏死因子-α（tumor necrosis factorα,TNF-α）表达量变化的分析。结果：炎症程度方面消毒组0级,两组粪肠球菌再感染1周时即高达3级,于4周时降为2级,至6周时非溶血组降为1级（同慢性根尖周炎组）,而溶血组仍为2级;TNF-α在消毒组表达量最低,在2组再感染组中的变化为：1-3周均高表达,2周时最甚,4周逐渐降低,各时间点中溶血组表达量均较非溶血组高,且2组均强于慢性根尖周炎组。结论：溶血素可影响粪肠球菌再感染根尖周炎的自愈能力;TNF-α的表达量与根尖周炎炎症破坏程度相关。

Objective：To compare the inflammatory progress and the expression of TNF-αin rat-reinfected periapical periodontitis models induced by different genotypes of Enterococcus faecalis（E.faecalis）.Methods：After pulp exposure of the bilateral maxillary first molars of rats for 3weeks,the molars were divided to 4groups：disinfection group,chronic apical inflammation group,hemolytic E.faecalis reinfected group and nonhemolytic E.faecalis reinfected group.Then the hematoxylin-eosin staining and immumohistochemical staining of TNF-αwere conducted.Results：The inflammation degree of the disinfection group was 0.After 1week in both reinfected groups,the inflammation degree reached to 3,and it lasted to the 3rd week.When E.faecalis was reinfected at the 4th week,the inflammation degree was dropped to 2.It was noticed that the inflammation degree of the nonhemolytic group at the 6th week was reduced to 1which was the same as chronic apical inflammation group,while the degree of the hemolytic group maintained at level 2at the same time.The expression of TNF-αwas the lowest in the disinfection group.The expression of TNF-αin both reinfected groups was higher than that of the chronic group.At the second week,the expression of TNF-αin both reinfected groups reached the climax,and then decreased.The expression of TNF-αin hemolytic group was higher than that in nonhemolytic group at all time points.Conclusion：Cytolysin（Cyl）may influence the healing progress of E.faecalis reinfected periapical periodontitis and prolong the inflammation process.The expression of TNF-αwas related to the inflammation progression of E.faecalis reinfected periapical periodontitis.