齿龈内阿米巴引起牙周炎及其致病机制的研究

STUDIES ON PERIODONTITIS CAUSED BY ENTAMOEBA GINGIVALIS AND ITS PATHOGENETIC MECHANISM

目的 研究齿龈内阿米巴 ( Entamoeba gingivalis,E.g.)与牙周炎的关系及其致病机制。 方法 给大鼠免疫抑制剂 ,于下颌切牙颈部结扎细钢丝 ,在 E.g.组和对照组大鼠龈缘涂抹 E.g.或生理盐水 ,观察大鼠发病和病理改变情况 ;检测感染 E.g.的牙周炎患者唾液中的超氧化物歧化酶 ( SOD)、过氧化氢酶 ( CAT)、酸性磷酸酶 ( ACP)和丙二醛 ( MDA)含量 ;应用电镜细胞化学技术观察 E.g.的细胞器。 结果 大鼠牙龈上皮组织溃疡、炎症细胞浸润、牙龈沟内上皮增生、牙周脓肿形成、牙槽骨吸收和脓液查见活 E.g.,对照组未见病理改变 ;感染 E.g.的牙周炎患者的 SOD较正常组低 ( P<0 .0 1) ,而 CAT两组间差异不明显 ( P>0 .0 5 ) ,ACP与 MDA含量显著高于正常组 (均 P<0 .0 1) ;E.g.的伪足粘附、伸入口腔上皮细胞微绒毛之间 ,溶酶体标志酶反应阳性。 结论 当宿主免疫力降低时 ,E.g.可致宿主牙周炎。虫体伪足的活动 ,溶酶体含 ACP等水解酶对牙周组织的溶解、破坏与氧自由基对细胞膜的损害是虫体引起牙周炎的重要致病机制。

Objective To study the relations between Entamoeba gingivalis(E.g.) and periodontitis and its pathogenetic mechanism. Methods After being treated with immuno-inhibitor, the necks of mandibular incisor of the rats were ligated with a thin steel wire. The gingival margin was smeared with E.g. or physiological saline. Conditions and histopathological changes were observed. Contents of superoxide dismutase(SOD), catalase(CAT), acid phosphatase(ACP) or maldondiadehyde(MDA) in saliva collected from the patients with periodontitis infected with E.g. were tested. Organelles of E.g. were observed by electron microscopic cytochemistry. Results The rats gingival epithelial tissue: ulcerated, inflamed cells were infiltrated, epithelium in gingival channel proliferated, periodontal abscess formed, alveolar bone was absorbed. Living E.g. was found in the abscess liquid. There was no pathological change in control group. The contents of SOD of patients with periodontitis infected with E.g. were lower than those of normal group(P<0.01), no significant differences in CAT between two groups(P>0.05). ACP and MDA of patients with periodontitis infected with E.g. were higher than those of normal group(P<0.01, P<0.01). Pseudopod of E.g. adhered to and stretched out to the space among micro-villi of oral epithelium cells. Marked enzyme of lysosome had positive reaction. Conclusion E.g. can cause periodontitis in hosts with low immunity. Activities of pseudopod of E.g., lyses and destruction of periodontal tissue caused by hydrolase of lysosome containing ACP etc. and damage of the cellular membranes done by oxygen free radicals are the important pathogenic mechanism of periodontitis caused by E.g.. (For Fig. 1-6, to see back cover inside)