Effects of neonatal exposure to anti-nerve growth factor on the number and size distribution of trigeminal neurones projecting to the molar dental pulp in rats
Effects of neonatal exposure to anti-nerve growth factor on the number and size distribution of trigeminal neurones projecting to the molar dental pulp in rats
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DOI：
10.1016/0003-9969(95)00128-x
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发表时间：
1996-04-01
影响因子：
3
通讯作者：
Naftel, JP
中科院分区：
文献类型：
--
作者：
Qian, XB;Naftel, JP
本研究的第一个目的是确定是否耗尽内源性神经生长因子（NGF）在出生后早期的发展结果在长期赤字的数量三叉神经节细胞和轴突投射到磨牙牙髓。第二个目的是确定选择性的神经生长因子剥夺的影响，任何特定的大小组之间的牙髓神经元。给新生Sprague-Dawley大鼠皮下注射兔抗小鼠NGF血清或非免疫（对照）兔血清，持续1个月。在4个月大时，将荧光金（FG）应用于右侧上颌第一磨牙的髓室。一周后，将动物灌注固定，取出三叉神经节并用低温恒温器连续切片。标记的神经元只出现在注射牙齿同侧的三叉神经节。测量每个标记细胞轮廓的面积，并从这些数据中，通过递归转换获得FG标记细胞的真实数量和大小分布的估计值。对照组动物的神经节平均有197个标记的神经元，全部位于上颌部，大多数胞体直径中等或较大。神经生长因子剥夺的动物有显着减少（平均值= 145）FG标记的细胞在三叉神经节同侧注射的牙齿。胞体直径小于30 μ m的神经元在抗NGF治疗的动物中最显着低于正常（对照组的64%）。按照更大的敏感性小神经元抗神经生长因子的曝光，在下颌第一磨牙的根尖神经纤维的赤字更大的程度和持续时间为无髓轴突比有髓轴突。结论：神经生长因子是牙髓感觉神经支配发育的重要调节因子。结果还表明，至少一类较大的牙髓传入神经元的出生后发育受到NGF以外的因素的调节。版权所有（C）1996 Elsevier Science Ltd.
The first aim of the present study was to determine whether depletion of endogenous nerve growth factor (NGF) during early postnatal development results in a long-term deficit in the number of trigeminal ganglion cells and axons projecting to the molar pulp. The second aim was to identify selectivity of the effects of NGF deprivation for any specific size group among pulp neurones. Newborn Sprague-Dawley rats were given subcutaneous injections of either rabbit anti-mouse-NGF serum or non-immune (control) rabbit serum for a period of 1 month. At age 4 months, Fluoro-gold (FG) was applied to the pulp chamber of the right maxillary first molar. One week later, the animals were perfusion-fixed, and the trigeminal ganglia were removed and serially sectioned with a cryostat. Labelled neurones were seen only in the trigeminal ganglia ipsilateral to the injected teeth. The area of every labelled cell profile was measured, and from these data, estimates of the true number and size distribution of FG-labelled cells were obtained by recursive translation. Ganglia of control animals had a mean of 197 labelled neurones, all in the maxillary division, and most of the somas were of medium or large diameter. NGF-deprived animals had significantly fewer (mean = 145) FG-labelled cells in the trigeminal ganglion ipsilateral to the injected tooth. Neurones with somas of less than 30 mu m dia were most strikingly subnormal in anti-NGF treated animals (64% of controls). In accordance with the greater susceptibility of small neurones to anti-NGF exposure, deficits in apical nerve fibres of the mandibular first molar were greater in degree and duration for unmyelinated axons than for myelinated axons. It is concluded that NGF is an important mediator in regulation of postnatal development of the sensory innervation of the dental pulp. The results also indicate that postnatal development of at least one class of larger pulpal afferent neurones is regulated by factors other than NGF. Copyright (C) 1996 Elsevier Science Ltd.