下颌神经切断术后Ⅰ型囊泡膜谷氨酸转运体在大鼠三叉神经复合体中表达的变化

CHANGES OF EXPRESSION OF VESICULAR GLUTAMATE TRANSPORTER 1 IN THE RAT TRIGEMINAL COMPLEX AFTER MANDIBULAR NERVE TRANSECTION

目的观察下颌神经切断术后不同存活时间I型囊泡膜谷氨酸转运体(VGluT1)样免疫阳性物质在大鼠三叉神经复合体中表达水平的变化。方法免疫细胞化学和图像分析技术。结果正常大鼠三叉神经复合体内可观察到大量的VGluT1样免疫阳性物质,且主要分布于终末内。切断一侧下颌神经后,手术侧与对照侧相比,术后存活1周组的Vp背侧部内VGluT1样阳性物质的表达有所下降(P<0.05);术后存活2周组的Vp背侧部、Vc背侧部、Vi背侧部,以及Vsup和Vmo内VGluT1样阳性物质的表达明显下降(P<0.01),且与术后存活1周组手术侧比较其下降有显著差异(P<0.05);术后存活3周组上述部位内VGIuT1样阳性物质表达的下降更加明显(P<0.01),且与前两组手术侧相比均有显著差异(P<0.01或P<0.05);其中在Vmo内的表达几乎完全消失。结论切断初级传入神经元的周围突可以导致其中枢突终末内VGluT1的表达水平下降;三叉神经复合体内部分VGIuT1样阳性终末来源于外周。

Objective The changes of VGluT1-like immunoreactivity（VGluT1-LI） in the trigeminal complex of the rat in different survival time after unilateral mandibular nerve transection were examined. Methods Immunocytochemical staining method and image analysis technique were performed. Results Many VGIuT1-LI were observed in the trigeminal complex of the normal rat and were mainly distributed in the terminals. A weak decrease of VGIuT1-LI in the dorsal part of principal trigeminal nucleus （Vp） could be detected at the first week after unilateral transection of mandibular nerve（ P 〈 0.05）. From two weeks after the transection, a sharp decrease of VGIuT1-1R was shown not only in the dorsal part of caudal spinal trigeminal nucleus （Vc） and interpolar spinal trigeminal nucleus （Vi）, but also in the supratrigeminal nucleus （Vsup） and the motor trigeminal nucleus （Vmo） besides the dorsal part of Vp （ P 〈 0.01 ）, and the reduction of VGluT1-1R on the ipsilateral side was much more evident than those observed at the first week （ P 〈 0.01 ）. The decrease of VGluT1-IR was much significant at three weeks after transection （ P 〈0.01）, and the decrease on the ipsilateral side was much more evident than those observed at the first and two weeks（ P 〈 0.01 ）. The VGluTI-IR almost disappeared in Vmo. Conclusion （ 1 ） Transection of the peripheral branches of primary afferent neurons could induce down-regulation of VGluT1-IR in their central terminals. （2）Part of VGluT1-immunoreactive terminals in trigeminal complex originated from the primary afferent neurons.