功能矫治器前伸大鼠下颌后咬肌中BDNF表达变化的研究

The changes of BDNF expression in masseter muscles after functional mandibular advancement

目的:观察功能矫治器前伸青春期大鼠下颌对咬肌中脑源性神经营养因子(brain-derivedneurotropic factor,BDNF)表达的影响。方法:将40只4周龄雄性SD大鼠随机分为实验3 d组、7 d组、14 d组、21 d组和同步正常对照组,共8组(n=5)。实验组大鼠佩戴功能矫治器,建立下颌前伸动物模型;建模不同时间用免疫组织化学染色和RT-PCR检测各组大鼠咬肌中BDNF蛋白及其mRNA的表达水平。结果:与对照组相比,实验3 d组、7 d组BDNF蛋白和mRNA的表达均无显著性差异(P>0.05);而实验14 d组、21 d组BDNF蛋白及mRNA表达水平均明显高于对照组(P<0.05)。结论:功能矫治器前伸下颌可使大鼠咬肌BDNF的表达水平随前伸时间的延长而逐渐增加,提示咬肌在下颌前伸中发生了适应性的改建活动。

AIM： To investigate the changes of brain-derived neurotropic factor（BDNF） expression in masseter muscle fibers of adolescent rats after functional mandibular advancement. METHODS ： Forty 4-week-old Sprague-Dawley rats were randomly assigned to experimental and control groups. The functional appliances for mandibular advancement were used in experimental groups for 3,7,14 and 21 days respectively, the corresponding control rats were not treated （n = 5 ）. Immunohistochemistry staining method and RT- PCR were used to detect the BDNF protein and mRNA expression in rat masseter muscles. RESULTS： The protein and mRNA expression of BDNF in 3 d and 7 d groups showed no difference between experimental and control groups, However, both protein and mRNA of BDNF were significantly higher in experimental 14 d and 21 d groups than those in corresponding control groups （P 〈 0.05 ）. CONCLUSION： The functional mandibular advancement can time-dependently increase the expression of BDNF in masseter muscles of adolescent rats. These changes may contribute to the proprioceptive adaptation to masseter muscle rebuilding.