中文摘要：

目的：探讨引导大鼠下颌前伸后，髁突软骨中血管内皮细胞生长因子爱体Ⅱ（KDR／Flk-1）表达水平的变化。方法：50只35天龄雄性SD大鼠随机分为5组，每组随机分为实验组（5只）和对照组（5只）；实验组大鼠24h佩戴自制功能性矫治器引导下颌前伸：实验后3、7、14、21和30天分别处死各组大鼠；免疫组化方法检测髁突软骨中Flk-1的表达情况。结果：对照组髁突软骨Flk-1表达随时间延长而减弱，后部区域Flk-1表达强于前部和中部；实验后第14天，21天和30天实验组Flk-1表达强于相应对照组（P〈0．05），21天时其增强幅度最大。结论：下颌前伸后大鼠髁突软骨细胞Flk-1表达增强，说明其介导了VEGF引发的软骨内骨化过程。

英文摘要：

Objective To investigate the temporal pattern of expression of Vascular Endothelial Growth Factor Receptor Ⅱ （KDR/Flk-1） in the condyle of rat during forward mandibular positioning. Methods Fifty 35-day-old male Spague-Dawley （SD） rats were randomly divided into 5 groups.Each group consisted of 5 rats with bitejumping appliance and 5 untreated as the control. One group was sacrificed on days 3, 7, 14, 21 and 30 respectively. Immunostaining was performed to detect the expression level of FIk-1. Results The expression level of Flk-1 in control groups decreased during the experimental periods with higher expression in posterior region compared to anterior and middle regions.Mandibular advancement in rats caused a gradual increase in the expression of Flk-1 when compared to the control group （P〈0.05）,with the highest amount of changes in the posterior region on Day 21. Conclusion Mandibular advancement in rats caused cellular changes of condyle,which led to increased Flk-1 expression and endochondral ossification.