摘要
目的观察先天性马蹄内翻足大鼠支配腓肠肌的脊髓运动神经元数量和形态的变化,为先天性马蹄内翻足病因学说中神经肌肉病变学说的研究提供客观依据。方法用全反式维甲酸(alltrans-Retinoicacid,at-RA)诱导大鼠产生先天性马蹄内翻足动物模型,将胎儿外科与显微注射技术相结合,对正常胎鼠和先天性马蹄内翻足胎鼠支配腓肠肌的脊髓运动神经元用荧光金(fluorogold,FG)进行逆行性神经示踪,留取脊髓标本进行冰冻切片,在荧光显微镜下进行FG标记神经元的定量计数和形态观察。结果荧光金标记的神经元主要分布在脊髓前角腹外侧区。RA致畸组中合并神经管发育异常的胎鼠,脊髓冰冻切片未计数到形态正常的FG标记神经元,实验中共有10只胎鼠;未合并神经管发育异常的胎鼠脊髓冰冻切片可观察到FG标记神经元,计数的实验胎鼠数量为25只,其神经元数量比对照组减少、细胞体积较小、突触间联系减少。神经元计数结果为:对照组FG标记神经元数量为(441±222)个;RA致畸组FG标记神经元数量为(266±134)个。结论腰骶段脊髓运动神经元的发育异常可能直接影响其支配部位的肌肉,产生肌肉结构异常和功能障碍,引起肌力不平衡导致足部骨骼形态的改变,最终形成先天性马蹄内翻足畸形的病理改变。
Objective To study the morphological changes of motor neurons innervating the gastrocnemius in rats with congenital clubfoot. Methods Congenital clubfoot malformation is induced in fetuses by gavaging the pregnant Wistar rats with all trans - Retinoic acid （ 120 mg/kg body weight） at gestational day 10. Fetal surgery was performed. 50% Fluorogold（FG）was injected into the gastrocnemius of both normal fetuses and congenital clubfoot fetuses for retrograde tract-tracing. Sample of spinal cords were removed for cryosection. The quantity and morphology of FG-lablled motoneurons were determined under fluoro - microscope. Results The FG- labled motor neurons were localized mainly in the ventro-lateral zone of the lumbosacral spinal cord. The number of FG-lablled motor neurons in 1 ） fetuses with congenital clubfoot and neural tube defects, 2） fetuses with congenital clubfoot only and 3） in normal controls were 0, （266 ＋ 134） and （441 ＋ 222）, respectively. Fetuses with congenital clubfoot have fewer FC--labled motor neurons than the normal controls （P〈0. 05）. At the same time, the cells are smaller and the synapses between neurons are fewer than those in normal controls. Conclusions From the result of this experiment, we hypothesize that the malformation of lumbosacral spinal cord may influence the muscle development of the lower limbs. The imbalance of muscle power may lead to congenital clubfoot both in human and in laboratory animal.
出处
《中华小儿外科杂志》
CSCD
北大核心
2005年第8期427-430,共4页
Chinese Journal of Pediatric Surgery
基金
"国家重点基础研究发展规划"项目课题名称:致畸性疾病
编号:2001CB510301
