关节盘穿孔致大鼠颞下颌关节骨关节病的形态学及组织病理学观察

目的通过关节盘穿孔建立大鼠颞下颌关节骨关节病(temporomandibular joint osteoarthrosis,TMJOA)模型,并观察颞下颌关节(temporomandibular joint,TMJ)髁突的形态学特征及组织病理学变化。方法8只12周龄雄性SD大鼠购自重庆医科大学,体质量200~250 g,通过随机数表法将其分为1周组和4周组,每组各4只。用齿科慢机球钻在每只大鼠左侧(模型侧)关节盘中后部形成直径1.5 mm的规则圆形穿孔,右侧(对照侧)不予处理。1周组和4周组大鼠分别于处理后1、4周时处死,获取双侧TMJ组织,通过形态学观察、影像学检查分析关节软骨的退化程度及软骨下骨的结构变化。通过免疫组织化学染色、苏木精染色、番红O-固绿染色、抗酒石酸酸性磷酸酶(tartrate-resistant acid phosphatase,TRAP)染色,分析大鼠TMJ髁突软骨的组织病理学变化。结果形态学观察显示1周组模型侧关节盘红肿明显,4周组模型侧可见典型的骨关节病鸟嘴样改变,1周组和4周组模型侧髁突的高度分别为(2.73±0.14)和(2.49±0.25)cm]均显著低于对照侧分别为(3.30±0.09)和(3.30±0.12)cm](P<0.01);影像学结果显示4周组模型侧骨小梁微观结构破坏明显;番红O-固绿染色结果显示1周组及4周组模型侧的蛋白聚糖均显著低于对照侧(P<0.01);TRAP染色结果显示1周组及4周组模型侧的破骨细胞数目均显著多于对照侧(P<0.01);免疫组织化学染色、苏木精染色结果显示1周组及4周组模型侧的胶原纤维密度较对照侧均显著减少(P<0.01),而基质金属蛋白酶显著增多(P<0.01)。结论大鼠关节盘穿孔后,模型侧髁突软骨出现了典型的TMJOA病理改变。

Morphological and histopathological evaluation of temporomandibular joint osteoarthrosis induced by perforation of articular disc in rats

Objective To establish the animal model of temporomandibular joint osteoarthrosis(TMJOA)in rats induced by perforation of articular disc and evaluate the morphological characteristics and histopathological changes of the condyle of temporomandibular joint(TMJ).Methods Eight male SD rats,purchased from Chongqing Medical University,were marked from No.1 to No.8 according to a random number table.The eight numbered rats were then arranged according to their sizes from large to small.The first four rats were divided into the one-week group,while the last four were divided into the four-week group.In order to simulate a TMJ disc perforation,an oblique incision was created along the zygomatic arch of the left side(the model side)making the TMJ superior joint space exposed.The left disc was pulled out and artificially perforated by a dental round bur with 1.5 mm diameter at the postmedian part of TMJ disc.The disc of the right side(the control side)was kept intact.The rats were randomly euthanized respectively at 1 week or 4 weeks(n=4 for each time point)for further study.Morphological observation and imaging examination were used to assess the degree of articular cartilage degradation and the loss of subchondral bone.Immunohistochemicalstaining(IHC),safranin O and fast green staining,tartrate-resistant acid phosphatase(TRAP)staining and haematoxylin staining were performed to evaluate the histopathological changes of condylar cartilage.Results In the morphological observation,significant redness and swelling were observed on the model side of the 1-week-group and the typical beak-like change of osteoarthropathy was observed on the model side of the 4-week-group.The heights of condylar process on the model sides in the 1-week-group and 4-week-group(2.73±0.14)and(2.49±0.25)cm,respectively]were significantly lower than that in the control side(3.30±0.09)and(3.30±0.12)cm,respectively](P<0.01).Imaging examination showed obvious damage in trabecular microstructure on the model side of the 4-week-group.Safranin O and fast green staining showed that the amounts of proteoglycan on the model sides of the 1-week-group and the 4-week-group were significantly lower than that on the control sides(P<0.01).TRAP staining showed that the numbers of osteoclasts on the model side of the 1-week-group and the 4-week-group was significantly higher than that on the control sides(P<0.01).IHC staining and Haematoxylin staining showed that the mean optical densities of collagen on the model side of the 1-week-group and the 4-week-group was significantly reduced compared with that on the control sides(P<0.01),while the mean optical densities of matrix metalloproteinase increased significantly(P<0.01).Conclusions After making a articular disc perforation,the condylar cartilage on the model side presented typical TMJOA pathological changes.