Ontogenic changes in injury-induced gene expression

描述(由申请人提供)：为重症婴儿患者开发治疗方法的困难之一是对婴儿和成人之间的疼痛处理方式的差异了解有限。特别是，在疼痛的处理方式和组织侮辱的长期后果方面，存在着发育差异。来自临床和实验室的越来越多的证据表明，在婴儿受伤后，对随后的有害刺激的敏感性有长期的变化。此外，至少在老鼠身上，似乎有一个“关键”时期，例如，在生命的头两周受到伤害，但不是在以后，会导致疼痛敏感性的长期变化。这显然具有非常重要的临床意义；然而，人们对早期发育过程中疼痛经验所涉及的机制一无所知。最近发展的微阵列方法可以同时评估数千个基因的表达变化，这为确定神经和遗传变化提供了一个独特的机会，这些变化可能导致婴儿在受伤后立即和24小时内以及成年后疼痛处理方面的差异。在这里，我们建议使用特征明确的寡核苷酸微阵列(Affymetrix)和最先进的分析方法来定义损伤诱导的基因表达变化。我们将腰椎膨大的背角作为一个模型系统，这主要是因为所描述的损伤引起的脊髓功能和神经生物学的短期和长期变化。我们在3日龄和21日龄时对小鼠进行测试，并在超过24小时的时间内四次评估受侮辱后基因表达的变化。这将基因表达的更直接变化描述为损伤的函数。第二个系列的研究考察了发育早期不同年龄的幼崽在成年脊髓中基因表达的变化。在假定的关键时期，在生命的头两周，幼崽被注射卡拉胶。年龄较大的幼崽会接受测试，因为它们处于关键期之外。无论有没有受到侮辱，被当作幼崽对待的成年犬都会再次接受测试，并通过微阵列分析基因表达。这些实验的结果将详细定义伤害在发育早期引起的基因表达的变化，当时伤害过程与成人明显不同，在发育后期，在关键期结束后，再一次。此外，我们描述了表达的长期变化，这可能解释了早期损伤引起的痛觉的“永久性”变化。这些数据将为合理的治疗提供基础，这些治疗可能会减少早产儿和重病婴儿痛苦经历的任何有害影响。

DESCRIPTION (provided by applicant): One of the difficulties in developing treatments for the seriously ill infant patient has been the limited understanding of how pain processing differs between the infant and the adult. In particular, there are developmental differences in how pain is processed, and in the long-term consequences of tissue insult. Growing evidence both from the clinic and the laboratory demonstrate that there are long lasting changes in sensitivity to subsequent noxious stimuli following injury in the infant. Further, there appears to be a "critical" period, at least in the rat, such than injury in the first two weeks of life, but not later, results in those long lasting changes in pain sensitivity. This clearly has very important clinical implications; yet nothing is known of the mechanisms engaged by the experience of pain in early development. The recent development of microarray methods to assess simultaneously changes in the expression in thousands of genes provides a unique opportunity to define the neural and genetic changes that might be responsible for the differences in pain processing in infants, immediately and in the 24 hours after injury, and into adulthood. Here we propose to use well-characterized oligonucleotide microarrays (Affymetrix) and state of the art analytic methods to define those alterations in gene expression induced by injury. We assay the dorsal horn of the lumbar enlargement of the spinal cord as a model system, largely because of described short and long terms changes in spinal cord function and neurobiology induced by injury. We test rat pups at 3 and 21 days of age and assess gene expression changes at four times after insult over 24 hours. This describes the more immediate changes in gene expression as a function of injury. The second series of studies examine changes in gene expression in the adult spinal cord in pups injured at different ages in early in development. In the putative critical period, during the first two weeks of life, pups are injected with carrageenan. Older pups are tested because they are outside the critical period. Adults treated as pups are tested again, with or without insult, and gene expression is assayed by microarray. The results of these experiments will define in detail, changes in gene expression that are induced by injury early in development when nociceptive processes are distinctly different than the adult, and again later in development, after the end of the critical period. Further, we describe long-term changes in expression that might explain the "permanent" changes in pain perception induced by early injury. These data will provide the basis of rational treatments that might reduce any deleterious effects of pain experience by premature and seriously ill infants.