Larkowski T D, Drengler S M, Tanzer L, Jones K J
Department Cell Biology, Neurobiology, and Anatomy, Loyola University Chicago, Stritch School of Medicine, Maywood, Illinois 60153, USA.
J Neurobiol. 2000 Dec;45(4):207-14. doi: 10.1002/1097-4695(200012)45:4<207::aid-neu2>3.0.co;2-v.
Testosterone propionate (TP) administration at the time of facial nerve injury in the adult hamster augments the regenerative properties of the injured facial motoneurons (FMN), with the androgen receptor (AR) playing a key role in mediating the actions of TP on facial nerve regeneration. The purpose of the present study was to determine the effects of axotomy on AR mRNA expression in FMN. This was accomplished using in situ hybridization in conjunction with a (35)S-labeled AR riboprobe. Gonadally intact adult male and gonadectomized (gdx) adult female hamsters were subjected to a right facial nerve axotomy, with the left side serving as internal, unoperated control. Half the animals were subcutaneously implanted with a 10-mm TP Silastic capsule, and the other half were sham-implanted. An additional group of nonaxotomized, gonadally intact males was also included. Postaxotomy survival times were 1, 4, and 7 days. At 1 postoperative day 1, there were no effects of axotomy on AR mRNA levels. By postoperative days 4 and 7, axotomy caused a significant decrease in AR mRNA levels in FMN of gonadally intact males, relative to either the contralateral control FMN of the same animals or FMN from the group of gonadally intact males that were not subjected to facial nerve axotomy. There were no significant differences between AR mRNA levels in contralateral control FMN and FMN from the gonadally intact group of nonaxotomized males. TP administration at the time of axotomy had no effect on AR mRNA levels in either the axotomized or contrala(teral control FMN of gonadally intact males, relative to the nonaxotomized, gonadally intact male group. Corroborating our previous work, AR mRNA levels were reduced in the contralateral control FMN of gdx females, relative to the nonaxotomized, gonadally intact male group, with axotomy having no additional effects. The data are discussed in a mechanistic framework suggesting how TP acts to augment facial nerve regeneration.
成年仓鼠面神经损伤时给予丙酸睾酮（TP）可增强受损面神经运动神经元（FMN）的再生特性，雄激素受体（AR）在介导TP对面神经再生的作用中起关键作用。本研究的目的是确定轴突切断术对FMN中AR mRNA表达的影响。这是通过原位杂交结合（35）S标记的AR核糖探针来完成的。将性腺完整的成年雄性和去势成年雌性仓鼠进行右侧面神经轴突切断术，左侧作为未手术的内部对照。一半动物皮下植入10毫米的TP硅橡胶胶囊，另一半进行假植入。还包括另一组未进行轴突切断术的性腺完整雄性动物。轴突切断术后的存活时间为1、4和7天。在术后第1天，轴突切断术对AR mRNA水平没有影响。到术后第4天和第7天，与同一动物的对侧对照FMN或未接受面神经轴突切断术的性腺完整雄性动物组的FMN相比，轴突切断术导致性腺完整雄性动物的FMN中AR mRNA水平显著降低。对侧对照FMN和未进行轴突切断术的性腺完整雄性动物组的FMN中的AR mRNA水平没有显著差异。轴突切断术时给予TP对性腺完整雄性动物的轴突切断或对侧对照FMN中的AR mRNA水平没有影响，相对于未进行轴突切断术的性腺完整雄性动物组。与我们之前的工作一致，相对于未进行轴突切断术的性腺完整雄性动物组，去势雌性动物的对侧对照FMN中AR mRNA水平降低，轴突切断术没有额外影响。数据在一个机制框架中进行了讨论，该框架表明TP如何作用以增强面神经再生。
