Objective To investigate the effect of gradually induced disordered occlusion (GIDO) on the expression of osteoprotegerin (OPG) and receptor activator of nuclear factor-KB ligand(RANKL) in mandibular condylar cartilage of rats. Methods Totally 48 rats, aged 8 weeks were included, and were divided into experimental and control groups randomly at 4 time points, with same gender distribution (n=3). By inserting elastic rubber band the right side mandibular first molar and the left side maxillary first molar were moved mesially. Four weeks later, the right side mandi- bular third molar and the left side maxillary third molar were moved distally with same method. In this way, the GIDO was established in rats. The rats were sacrificed at the end of 2th, 4th, 6th and 8th week respectively- after the application of the GIDO. The expression of OPG and RANKL in condylar cartilage was examined with immunohistochemical method and calculated by the area of positive cell percentage. Results OPG and RANKL expressed predominantly in condylar cartilage hypertrophic layer. The rats in experimental group expressed a higher OPG level in all of the 4 time points than their age-matched controls (P<0.05), while RANKL were higher in 2, 6, 8 weeks subgroups (P<0.05), but not in 4 weeks subgroup. No differences were found between male and female subgroups. Conclusion The present results suggest that both OPG and RANKL take part in the condylar cartilage remodeling procedure in the present rat model.%目的 探讨渐进性咬合紊乱对大鼠髁突软骨中护骨素(OPG)及核因子-KB受体活化因子配体(RANKL)表达的影响.方法 选取48只8周龄大鼠,雌雄各半,随机分为实验组和对照组.推右侧下颌、左侧上颌第一磨牙近中移动,4周后同样方式推右侧下颌、左侧上颌第三磨牙远中移动,建立渐进性咬合紊乱动物模型.实验2、4、6、8周后,每组、每性别各处死3只动物.免疫组织化学方法、阳性细胞面积百分比法分析髁突软骨中OPG、RANKL的表达特点.结果 OPG和RANKL均表达于髁突软骨的肥大层,实验组OPG总体较对照组表达显著增多(P＜0.05);实验2、6、8周组RANKL较对照组表达明显增多(P＜0.05),实验4周组与对照组差异无统计学意义,雌雄性变化趋势相同.结论 OPG和RANKL均参与了异常咬合所导致的髁突软骨病理性改建活动.
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