Bengston L, Lopez V, Watamura S, Forger N G
Department of Psychology, University of Massachusetts, Amherst 01003, USA.
J Neurobiol. 1996 Oct;31(2):263-73. doi: 10.1002/(SICI)1097-4695(199610)31:2<263::AID-NEU10>3.0.CO;2-J.
Motoneuron death in the spinal nucleus of the bulbocavernosus (SNB) and the dorsolateral nucleus (DLN) of the lumbar spinal cord is androgen regulated. As a result, many more SNB and DLN motoneurons die in perinatal female rats than in males, whereas treatment of newborn females with androgen results in a permanent sparing of the motoneurons and their target muscles. We previously observed that a neurotrophic molecule, ciliary neurotrophic factor (CNTF), also arrests the death of SNB motoneurons and their target musculature, at least in the short term. The present study compares the short- and long-term consequences of perinatal CNTF treatment on motoneuron number in the SNB, the DLN, and the retrodorsolateral nucleus (RDLN), a motor pool in the lower lumbar cord that does not exhibit hormone-regulated cell death. Female pups were treated with CNTF or vehicle alone from embryonic day 22 through postnatal day 6 (P6). Motoneuron number in the each nucleus was then determined immediately after treatment on P7, or 10 weeks later (P77). CNTF treatment significantly elevated motoneuron number in the SNB and DLN on P7; the volume of SNB target muscles on P7 was also greater in the CNTF-treated group. These effects were transient, however, as motoneuron number and ratings of muscle size were not different in CNTF-and vehicle-treated females on P77. Perinatal CNTF treatment did not alter cell number in the RDLN at either age. The finding that effects of CNTF on SNB and DLN motoneuron number are short lived contrasts with the permanent effects of early androgen treatment, and has implications for molecular models of the actions of androgen and neurotrophic factors on the developing spinal cord.
球海绵体肌脊髓核（SNB）和腰脊髓背外侧核（DLN）中的运动神经元死亡受雄激素调节。因此，围产期雌性大鼠中死亡的SNB和DLN运动神经元比雄性大鼠多得多，而用雄激素治疗新生雌性大鼠可使运动神经元及其靶肌肉永久保留。我们之前观察到，一种神经营养分子，睫状神经营养因子（CNTF），至少在短期内也能阻止SNB运动神经元及其靶肌肉组织的死亡。本研究比较了围产期CNTF治疗对SNB、DLN和后外侧背核（RDLN，腰脊髓下部的一个运动神经元池，其细胞死亡不受激素调节）中运动神经元数量的短期和长期影响。从胚胎第22天到出生后第6天（P6），对雌性幼崽单独给予CNTF或赋形剂。然后在P7治疗后立即或10周后（P77）确定每个核中的运动神经元数量。CNTF治疗显著提高了P7时SNB和DLN中的运动神经元数量；在接受CNTF治疗的组中，P7时SNB靶肌肉的体积也更大。然而，这些影响是短暂的，因为在P77时，接受CNTF和赋形剂治疗的雌性大鼠的运动神经元数量和肌肉大小评级没有差异。围产期CNTF治疗在两个年龄阶段均未改变RDLN中的细胞数量。CNTF对SNB和DLN运动神经元数量的影响是短暂的，这一发现与早期雄激素治疗的永久影响形成对比，并且对雄激素和神经营养因子对发育中的脊髓作用的分子模型具有启示意义。
