Zhu Xin-long, Bai Wan-zhu, Wu Fu-dong, Jiang Jin, Jing Xiang-hong
Shandong University of Chinese Medicine, Jinan 250021, China.
Zhen Ci Yan Jiu. 2010 Dec;35(6):433-7.
To investigate neuroanatomical characteristics of the primary sensory afferent and the motor neurons coming from and innervating acupoint "Chengshan" (BL 57) area in the rat by using cholera toxin subunit B conjugated with Alexa Fluor 488 (CTB-Alexa 488), a new generation of fluorescent neural tracing reagent.
Four male SD rats were used in the present study. Under anesthesia, 0.05% CTB-Alexa 488 (5 ML) was injected into the central part of the rear of the hind leg, a corresponding site of "Chengshan" (BL 57) in the human body. After 40-48 surviving hours, the rat's brain, spinal cord and dorsal root ganglia (DRGs) of the lumbar segments (L1-L6) were dissected following perfusion with 4% paraformaldehyde, cut into sections and observed under fluorescent microscope equipped with a digital camera. The neurons labeled by CTB-Alexa 488 were counted.
All CTB-Alexa 488 labeled neurons appeared in green under fluorescent filters of 450-490 and were located ipsilaterally on the injection side. The labeled primary sensory neurons were found in the DRGs at L4 (11 neurons) and L5 (35 neurons). Among them, 29 neurons (63.04%) were bigger, with their cell body diameters being 35-50 microm and 17 (36.96%) smaller, with their body diameters being lower than 35 microm. The labeled motor neurons were found to distribute in the mediolateral portion of lamina IX, forming a longitudinal column from L4 to L5. Of the observed 316 motor neurons, 259 (81.96%) belong to alpha type with their body diameters being 25-40 microm and 57 (18.04%) to gamma type with their body diameters being lower than 25 microm.
The CTB-Alexa 488-labeled primary sensory and motor neurons innervating acupoint "Cheng-shan" (BL 57) distribute in the DRGs of L4-L5. The present fluorescent tracing technique may be quite useful for investigating the neural characteristics of acupoints.
采用新一代荧光神经示踪剂霍乱毒素B亚基与Alexa Fluor 488偶联物（CTB-Alexa 488），研究大鼠“承山”（BL 57）穴区初级感觉传入神经元和运动神经元的神经解剖学特征。
本研究选用4只雄性SD大鼠。在麻醉状态下，将0.05% CTB-Alexa 488（5微升）注射到大鼠后腿后部中央，该部位相当于人体的“承山”（BL 57）穴。存活40 - 48小时后，用4%多聚甲醛灌注大鼠，然后解剖其脑、脊髓和腰段（L1 - L6）背根神经节（DRG），切成切片，在配备数码相机的荧光显微镜下观察。对CTB-Alexa 488标记的神经元进行计数。
在450 - 490荧光滤光片下，所有CTB-Alexa 488标记的神经元呈绿色，且均位于注射侧的同侧。在L4（11个神经元）和L5（35个神经元）的DRG中发现了标记的初级感觉神经元。其中，29个神经元（63.04%）较大，其细胞体直径为35 - 50微米，17个（36.96%）较小，其细胞体直径低于35微米。标记的运动神经元分布在脊髓灰质Ⅸ层的中外侧部分，从L4到L5形成一个纵向柱。在观察到的316个运动神经元中，259个（81.96%）属于α型，其细胞体直径为25 - 40微米，57个（18.04%）属于γ型，其细胞体直径低于25微米。
CTB-Alexa 488标记的支配“承山”（BL 57）穴的初级感觉和运动神经元分布在L4 - L5的DRG中。目前的荧光追踪技术可能对研究穴位的神经特征非常有用。
