Toll样受体⁃4抑制剂TAK⁃242对大鼠重度牙周炎骨吸收的影响

目的探讨Toll样受体?4(Toll like receptor?4,TLR?4)抑制剂TAK?242对大鼠重度牙周炎骨质吸收的影响,为重度牙周炎寻找辅助治疗手段提供实验基础。方法18只3周龄雄性Wistar大鼠随机分为3组(n=6),其中1组为正常对照组,另外2组以含有牙龈卟啉单胞菌(P.gingivalis)ATCC33277的5?0丝线结扎大鼠双侧上颌磨牙行重度牙周炎建模,分为牙周炎组、TAK?242组;TAK?242组从丝线结扎第1天起,通过尾静脉隔天注射1次溶于DMSO的TAK?242(2 mg/kg),另外两组注射相同体质量比例的DMSO溶剂,连续8周;第8周末处死3组大鼠,获取大鼠上颌骨标本,采用micro?CT扫描后三维重建,测量特定位点釉牙骨质界?牙槽嵴顶的距离评估骨丧失量,并对牙槽骨骨质相关参数和骨质微结构进行分析;组织学切片苏木精?伊(HE)染色观察牙周组织病理改变;甲基绿染色观察牙槽骨吸收情况;抗酒石酸酸性磷酸酶(TRAP)染色观察破骨细胞分布情况。结果Micro?CT定量分析显示:牙周炎组与TAK?242组牙槽骨吸收显著高于对照组;与牙周炎组相比,TAK?242组大鼠上颌第一磨牙近、远中根吸收位点的骨丧失均显著减轻(P<0.001),骨密度(P<0.05)与骨体积/总体积分数(P<0.01)显著增高,骨小梁数目与骨小梁厚度(P<0.01)相对增多,骨小梁分离度(P<0.01)和骨小梁结构模式指数显著降低。牙周炎组骨质呈现疏松多孔的蜂窝状结构,骨小梁结构恶化,向杆状结构转变;TAK?242组骨质微结构改善,骨量改善,骨小梁分布相对更致密,骨小梁结构与对照组更相似。HE染色发现牙周炎组与TAK?242组牙周附着丧失与牙槽骨吸收较对照组显著;与牙周炎组相比,甲基绿染色表明TAK?242组骨吸收减轻,TRAP染色显示破骨细胞浸润减少(P<0.001)。结论TLR?4抑制剂TAK?242能缓解大鼠重度牙周炎骨吸收,改善其多孔、稀疏、排列紊乱的炎症性骨小梁结构。

Investigating the effect of the Toll-like receptor-4 inhibitor TAK-242 on alveolar bone resorption in severe peri-odontitis in rats

Objective The goal of this study was to investigate the effect of the Toll?like receptor?4(TLR?4)inhibi?tor TAK?242 on bone resorption in severe periodontitis in rats in order to provide an experimental basis for finding new adjuvant treatments for severe periodontitis.Methods Eighteen three?week?old male Wistar rats were randomly divid?ed into three groups(n=6).One group was the control group,and the other two groups were modelled with severe peri?odontitis in bilateral maxillary molars ligated with 5?0 silk thread containing P.gingivalis ATCC33277(periodontitis and TAK?242 groups,respectively).The TAK?242 group was injected with TAK?242(2 mg/kg)in DMSO every other day through the tail vein from the first day of silk ligation,and the other two groups were injected with DMSO solvent at the same proportion of body weight for 8 consecutive weeks.At the end of the 8th week,rats in the 3 groups were sacri?ficed,and maxillary specimens were taken.Three?dimensional reconstruction was achieved after micro?CT scanning to measure the distance between the enamel cementum boundary and alveolar crest at specific sites to assess the amount of bone loss.The parameters related to alveolar bone and bone microstructure were analyzed,and the pathological changes of periodontal tissue were observed by hematoxylin?eosin(HE)staining.Alveolar bone resorption was observed by Methyl Green staining,and the distribution of osteoclasts was observed by anti?tartrate acid phosphatase double stain?ing(TRAP).Results Micro?CT quantitative analysis showed that alveolar bone resorption in the periodontitis group and TAK?242 group was significantly higher than that in the control group.Compared with the periodontitis group,bone loss of the mesial and distal root resorption sites of maxillary first molars was significantly reduced in the TAK?242 group(P<0.001),the bone mineral density(P<0.05)and bone volume/total volume fraction(P<0.01)were signifi?cantly increased,and the number of trabeculae and the trabeculae thickness(P<0.01)were relatively increased.The trabecular separation(P<0.01)and trabecular structure model index were significantly decreased.In the periodontitis group,the bone exhibited a sparse and porous honeycomb structure,with deterioration of the trabecular structure and a shift towards a rod?strength structure.In the TAK?242 group,the bone microstructure was improved,the bone volume was enriched,the distribution of trabeculae was relatively denser and the trabecular structure shared more similarities with the control group.HE staining displayed that the attachment loss and bone absorption were significantly higher in the periodontitis group and TAK?242 group than in the control group.Compared with the periodontitis group,MG stain?ing displayed significantly alleviated bone absorption in the TAK?242 group.TRAP staining showed that osteoclast infil?tration decreased in the TAK?242 group compared with the periodontitis group(P<0.001).Conclusions The TLR?4 inhibitor TAK?242 can alleviate bone resorption in severe periodontitis and improve the porous,sparse and disorganized inflammatory bone trabecular structure in rats.