Study on the effects of periodontal mechanoreceptors on maintenance of the system regulating jaw-movement and the regenerative medicine for the system

为了揭示牙周传入神经在咀嚼系统发育和维持中的一般作用，应用辣根过氧化物酶-麦胚凝集素示踪法，从出生后30至360天的ICR小鼠的下牙槽神经（IAN）的治疗或不治疗的单侧拔牙在出生后第20天。生后20 d拔根可使三叉神经感觉核复合体（TSNC）标记的TG和Me 5神经元及标记终末数目减少。此外，几种神经营养因子已被检查，以评估其在神经发育以及外周和中枢神经系统（CNS）再生中的功能。特别是，酸性和碱性成纤维细胞生长因子（FGF）的似乎有几个实验模型中的神经死亡的救援效果。实验结果表明，在拔牙窝内注射aFGF可恢复受拔牙影响的Me 5、TG神经元和TSNC的初级传入终末。结果提示，缺牙引起的感觉输入功能下降是导致咀嚼系统发育和维持功能紊乱的原因之一，aFGF可能是治疗这一现象的有效药物之一

To reveal the general role of the periodontal afferent in the development and maintenance of the masticatory system, the horseradish peroxidase-wheat germ agglutinin tracing method was applied from 30 to 360 days after birth to the inferior alveolar nerve (IAN) of ICR mice with or without treatment of the unilateral extraction of molars on the 20th postnatal day. Toot extraction on the 20th postnatal day decreased the numbers of labeled TG and Me5 neurons and labeled terminals of trigeminal sensory nuclear complex (TSNC}. Furthermore, several neurotrophic factors have been examined for assessing their functions in neural development as well as in the regeneration of peripheral and central nervous system (CNS). Particularly, acidic and basic fibroblast growth factor (FGF)s seem to have rescue effects on neural death in several experimental models. Expectedly, single injection of aFGF into the tooth-extracted socket restored the Me5, TG neurons and the primary afferent terminals of the TSNC affected by the tooth-extraction. From the present results, it is suggested that the decrease in the sensory input due to the tooth-loss cause the disorder of the development and maintenance of the masticatory system and aFGF may be at least one of potent reagents to rescue this phenomenon