正畸力作用下人牙髓组织中神经生长因子的表达

Expression of Nerve Growth Factor in Human Dental Pulp Tissues Following Orthodontic Force

目的检测正畸力作用下人牙髓组织中神经生长因子(nerve growth factor,NGF)的表达与分布,探讨NGF在正畸加力初期疼痛中的作用及机制。方法20例采用拔除上颌双侧第一前磨牙进行固定矫治的患者随机分为5组,分别作为正常对照组,正畸加力1d、3d、7d、15d组,在受力相应时段对双侧上颌第一前磨牙进行疼痛强度问卷调查后拔除并制备石蜡标本,采用免疫组化SABC法进行染色,计算机图像分析系统检测阳性细胞的平均光密度值(average optical density,AOD)及面密度值(area density,AD)。结果1d组测试牙有轻度疼痛,3d组疼痛敏感程度最强;对照组中NGF染色呈弱阳性,加力1d组牙髓中NGF即有较高水平表达,加力3d组牙髓NGF染色呈强阳性,加力7d后NGF表达明显减弱,加力15d后表达恢复到正常水平;NGF的表达强度(AOD)与疼痛强度呈显著正相关(r=0.868,P<0.01)。结论在正畸加力初期牙髓组织中NGF表达有所增强,且表达强度与疼痛强度密切相关。NGF可能参与了正畸加力初期疼痛过敏的调节。

Objective To detect the expression and distribution of nerve growth factor （NGF） in human dental pulp tissues and to analyze the role of NGF in orthodontic pain in the early stage following orthodontic force. Methods 20 patients were randomly assigned to control group and ld, 3d, 7d and 15d groups after orthodontics. According to Derringer＇s methods, orthodontic force （in the range of 0. 5-1N in a mesiat and extrusive direction） was applied to the upper first premolar teeth of the test groups. The test teeth were extracted after finishing pain questionnaire in the correspond- ing time. Immunohistochemical method （SABC method） was utilized to localize and examine the expression of NGF in the paraffin section of decalcifying dental tissue. Average optical density （AOD） and area density （AD） of the positive cells were analyzed quantitatively by image analysis system. Results Compared with control group, the pain intensity （PI） increased in ld group, reached the highest level in 3d group （P〈0. 05）and decreased gradually. The expression of NGF was low in control group, increased obviously in ld group （P〈0. 05）, reached the highest level in 3d group （P〈0. 05） and decreased greatly in 7d group. In 15d group NGF was as same as those in control group. NGF level in human dental pulp tissues had positive relation with pain intensity （r= 0. 868, P〈0. 01）. Conclusion The expression of NGF is upregulated in human dental pulp tissues following orthodontic force and NGF may participate in the regulation of pain in the early stage of orthodontic treatment.