PARTURITION INDUCED PELVIC FLOOR NEUROPATHY

盆腔器官脱垂(膀胱、阴道和直肠下降)以及与之相关的膀胱和肠道功能障碍是许多女性的问题。脱垂是由于盆底肌肉(主要是提肛肌)和结缔组织失去支持所致。考虑到产次与盆腔器官脱垂的高度相关性，我们的主要假设是在分娩过程中盆底神经损伤是盆腔器官和大小便失禁的易感条件。由于缺乏合适的动物模型，这一假说尚未得到严格的检验。最近，我们建立了松鼠猴作为分娩相关脱垂的模型。松鼠猴子被要求达到检查分娩引起的神经病变的特定目标。也有人建议在大鼠身上进行研究，以提供一种更便宜、神经学研究得更好、系统发育较低的物种，在这种物种中，建立所有哺乳动物共同的盆底神经支配的基本参数，例如，神经元对损伤的反应。尽管盆底神经支配对维持盆腔内脏支持和控制有明显的重要性，但对于正常的盆底神经支配仍有相当程度的混淆。虽然以前的研究主要集中在阴部神经及其在盆腔器官脱垂和大小便失禁中的损害，但我们的初步数据表明，肛提肌有明显的神经支配。因此，特定的目标1建议仔细定义提肛肌(LA)的周围神经支配，用逆行追踪技术识别LA运动神经元及其树突分支，用跨神经节追踪技术描述LA初级传入投射在脊髓中的中枢分布，并用逆行追踪结合免疫组织化学方法鉴定和表征LA初级传入神经元的递质表型。为了验证与分娩相关的LA神经损伤是脱垂的一个组成部分的假设，特定目标2将a)比较LA神经和阴部神经损伤造成的盆腔器官脱垂，b)确定实验诱导的LA初级传入神经元和运动神经元的细胞反应以及神经损伤后发生的肌肉变化，c)检测神经源性损伤标志物的表达和分娩后肌肉的变化，以及d)比较未脱垂的猴子和严重脱垂的猴子的神经源性损伤标志物和肌源性变化。具体目标3将研究与LA神经支配和去神经机制相关的神经营养因子系统，例如神经元凋亡、轴突萎缩等。

Pelvic organ prolapse (descent of the bladder, vagina, and rectum) and associated bladder and bowel dysfunction are problems for many women. Prolapse results from loss of support by pelvic floor musculature (predominantly levator ani muscles) and connective tissue. Given the high correlation between parity and pelvic organ prolapse, it is our overarching hypothesis that damage to the innervation of the pelvic floor during labor is a predisposing condition for pelvic organ and incontinence. This hypothesis has not been rigorously tested due to lack of a suitable animal model. Recently, we established the squirrel monkey as a model of parturition-associated prolapse. Squirrel monkeys are required to meet the specific aims that examine parturition-induced neuropathy. Studies are also proposed in the rat to provide a less expensive, neurologically well-studied, and phylogenitically lower species in which to establish basic parameters of pelvic floor innervation common to all mammals, e.g. neuronal responses to injury. Despite the obvious importance of pelvic floor innervation for maintenance of pelvic visceral support and continence, there is a considerable degree of confusion regarding normal pelvic floor innervation. While prior studies have thus focused on the pudendal nerve and its damage in pelvic organ prolapse and incontinence, our preliminary data suggest that the levator ani muscle has distinct innervation. Thus, specific aim 1 proposes to carefully define the peripheral innervation of the levator ani (LA), identify LA motor neurons and their dendritic arborizations using retrograde tracing techniques, describe the central distribution of LA primary afferent projections in the spinal cord using transganglionic tracing, and identify and characterize the transmitter phenotype of LA primary afferent neurons using retrograde tracing combined with immunohistochemistry. To test the hypothesis that parturition-associated damage to the LA nerves is a component of prolapse, specific aim 2 will a) compare pelvic organ prolapse produced by LA nerve versus pudendal nerve lesions, b) determine cellular responses of experimentally-induced nerve injury in LA primary afferent neurons and motor neurons and muscle changes that occur following nerve injury, c) examine expression of neurogenic injury markers and muscle changes following parturition, and d) compare neurogenic injury markers and myogenic changes in monkeys with no prolapse to those with severe prolapse. Specific aim 3 will examine neurotrophin systems associated with LA innervation and mechanisms of denervation, e.g. neuronal apoptosis, axonal atrophy, etc.