两种异常咬合刺激对小鼠髁突影像及组织形态学影响研究

Effect of two abnormal occlusion stimulations on the imaging and histomorphology of mice mandibular condyle

目的探究异常咬合刺激对小鼠髁突影像及组织形态学影响。方法选取6周龄雌性C57BL/6J小鼠36只,根据饲养时间(3、7周)均分小鼠后,再随机分为对照组、单侧前牙反(unilateral anterior crossbite,UAC)组和双侧前牙咬合抬高(bilateral anterior elevation,BAE)组,每组小鼠均为6只。对各组髁突软骨进行HE染色,Ⅱ型胶原(collagenⅡ,ColⅡ)免疫组织化学染色,Ⅹ型胶原(collagenⅩ,ColⅩ)和牙本质基质蛋白-1(dentin matrix protein-1,DMP1)免疫组织荧光染色,以及微型计算机断层扫描(micro-computed tomography,Micro-CT)成像。结果(1)Micro-CT结果显示:UAC组和BAE组软骨下骨的骨吸收均较相同饲养时间对照组增多。(2)HE染色结果显示:与相同饲养时间对照组比较,UAC组小鼠软骨细胞数量减少,排列紊乱,软骨厚度降低;BAE组浅层软骨细胞大量增加,软骨变厚。(3)免疫组织化学染色结果显示:与相同饲养时间对照组比较,UAC组ColⅡ表达减少;BAE组ColⅡ在3周表达升高,7周表达降低。(4)免疫组织荧光染色结果显示:与相同饲养时间对照组比较,UAC组ColⅩ和DMP1表达增加;而BAE组DMP1表达降低,ColⅩ的表达差异无统计学意义。结论UAC促进髁突软骨细胞向成骨分化,BAE未促进软骨内成骨;UAC和BAE均可造成髁突软骨下骨的骨丢失。

Objective To explore the imaging and histomorphology changes in mice mandibular condyle by abnormal occlusion stimulation.Methods Thirty-six 6-week-old female C57 BL/6 J mice were divided into two groups according to the feeding time(3 and 7 weeks),and then they were randomly divided into control,unilateral anterior crossbite(UAC) and bilateral anterior elevation(BAE) subgroups.There were six mice in each group.The condylar cartilage were randomly selected for HE staining,immunohistochemical staining of Col Ⅱ,immunofluorescence staining of Col X and DMP1 and micro-computed tomography(Micro-CT) imaging.Results(1) Micro-CT showed that subchondral bone absorption increased in both UAC and BAE groups compared with that of control group with the same feeding time.(2)HE staining showed that the UAC group had decreased chondrocytes number,disordered cell arrangement and thinner cartilage compared to control group with the same feeding time,while the BAE group had increased superficial chondrocyte number and thicker cartilage.(3)IHC staining showed that compared with control group with the same feeding time,Col Ⅱ expression increased in 3-week BAE group and decreased in UAC group and 7-week BAE group.(4)Immunofluorescence staining showed that the expression of Col X-and DMPl-positive cells increased in UAC group compared to control group with the same feeding time,while in BAE group,DMP1 expression reduced,but there was no significant difference in Col X expression.Conclusion UAC promotes osteogenic differentiation of chondrocytes,while BAE does not promote endochondral osteogenesis in cartilage.Moreover,these two stimulation both lead to the loss of condylar subchondral bone.