Effect of chronic low-dose phthalate exposure on the immature primate testis

长期低剂量邻苯二甲酸盐暴露对未成熟灵长类动物睾丸的影响

• 批准号: 7530079
• 负责人: INA DOBRINSKI
• 金额: $ 20.99万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-08 至 2009-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7530079
• 关键词: Adolescent; Affect; Animals; Attention; Biological Models; Catheterization; Cell Differentiation process; Cell Maturation; Cell physiology; Childhood; Chronic; Data; Development; Dibutyl Phthalate; Diethylhexyl Phthalate; Dose; Endocrine; Environment; Environmental Exposure; Epidemiologic Studies; Esters; Experimental Designs; Exposure to; Fertility; Food; Future; Gene Expression; Gene Expression Profiling; Genes; Genome; Germ Cells; Gonadotropins; Health; Human; Incidence; Infant; Intravenous; Investigation; Lead; Link; Long-Term Effects; Macaca; Macaca mulatta; Male Genital Organs; Metabolism; Microarray Analysis; Modeling; Molecular; Monkeys; Mus; Organ; Pathway interactions; Patients; Pattern; Perinatal Exposure; Phthalic Acids; Plasticizers; Plastics; Primates; Public Health; RNA; Rattus; Research; Research Design; Research Project Grants; Research Proposals; Reverse Transcriptase Polymerase Chain Reaction; Rodent; Rodent Model; Self Care; Somatic Cell; Steroid biosynthesis; System; Testicular Neoplasms; Testing; Testis; Time; Tissue Donors; Tissue Grafts; Tissue-Specific Gene Expression; Tissues; Toxic effect; Toxicology; Toy; Work; Xenograft Model; Xenograft procedure; age effect; base; consumer product; cost; dosage; exposed human population; human male; insight; leydig interstitial cell; male; medical supply; mono-(2-ethylhexyl)phthalate; nonhuman primate; novel; phthalate; phthalates; phthalic acid; reproductive; reproductive development; sertoli cell; toxicant

DESCRIPTION (provided by applicant): The objective of this exploratory research project is to study the effects of chronic exposure to phthalate esters on the infant primate testis in a novel xenograft model system. Environmental exposure to reproductive toxicants is of serious concern to human health and has been implicated in both the apparent decline of male fertility and a rise in testicular neoplasms. Phthalate esters are widely used as plasticizers in consumer products and can leach into the environment, resulting in significant human exposure, especially during childhood and in pediatric patients requiring long-term catheterization or intravenous treatments. Di-(2- ethylhexyl) phthalate (DEHP) is the most ubiquitous phthalate and its metabolite MEHP is a known testicular toxicant. Di-n-butyl phthalate (DBP) is commonly found in personal care products and fetal exposure to DBP affects male reproductive tract development in rats. Historically, research into the reproductive toxicology of phthalates has been evaluated following gestational exposure in rodents, but species-specific differences in metabolism and sensitivity of the reproductive organs suggest that results obtained in rodent models may not extrapolate well to humans. As epidemiological studies link phthalate exposure during childhood to disturbances of human male reproductive development, there is a clear need for studies in primate models, as emphasized by the NTP-CERHR Expert Panel on the Reproductive and Developmental Toxicity of DEHP. In this revised exploratory project we propose to utilize a novel primate testis tissue xenografting system developed in our lab to study the effect of DEHP and DBP on testicular maturation and testis function in immature rhesus monkey testes. Specific aim 1 will test the hypothesis that exposure to environmentally relevant concentrations of DEHP or DBP will adversely affect testicular somatic cell function and germ cell development. Specifically, testis tissue from infant and juvenile monkeys will be ectopically grafted to mouse hosts and exposed to various doses of DEHP or DBP for 3 months. At various time points, Sertoli cell maturation, steroidogenic function of Leydig cells, and exogenous gonadotropin-induced germ cell differentiation will be compared in treated and control tissue to assess the potential effects of chronic phthalate exposure. Specific aim 2 will investigate the mechanisms underlying phthalate toxicity in the infant primate testis. Phthalate-induced changes in global gene expression patterns in testis tissue from infant monkeys will be evaluated by microarray analysis and confirmed by RT-PCR. Special attention will be given to differential expression of genes involved in steroidogenesis. Successful completion of this exploratory project will provide insights into the sensitivity to phthalate esters, characterize effects on testicular somatic cell maturation, and begin to elucidate the molecular mechanisms underlying phthalate toxicity in the immature primate testis. Results from the proposed project will provide the basis for future studies performed in the developing primate. PUBLIC HEALTH RELEVANCE: Rodent models are conventionally utilized to study the potential effects of suspected reproductive toxicants, such as phthalates, on the immature human testis, but species-specific differences in metabolism and sensitivity of the reproductive organs may not make them ideal model systems. While studies in primates are more likely applicable to the human, they are often cost-prohibitive and ethically restrictive. In this research proposal we describe a novel system in which pieces of primate testis tissue are grafted into mice to investigate the mechanisms of reproductive phthalate toxicity in primate testis without extensive experimentation in primates.

描述(申请人提供)：本探索性研究项目的目的是在一个新的异种移植模型系统中研究长期暴露于邻苯二甲酸酯对婴儿灵长类动物睾丸的影响。环境中暴露于生殖毒物严重影响人类健康，并与男性生育力的明显下降和睾丸肿瘤的增加有关。邻苯二甲酸酯在消费品中被广泛用作增塑剂，可能会渗入环境，导致人体大量接触，特别是在儿童时期和需要长期导尿或静脉治疗的儿科患者中。邻苯二甲酸二(2-乙基己基)酯(DEHP)是最普遍存在的邻苯二甲酸酯，其代谢产物MEHP是已知的睾丸毒物。邻苯二甲酸二丁酯(DBP)普遍存在于个人护理产品中，胎儿暴露于DBP会影响大鼠的雄性生殖道发育。从历史上看，邻苯二甲酸酯的生殖毒理学研究是在啮齿动物怀孕后进行评估的，但物种特定的新陈代谢和生殖器官敏感性的差异表明，在啮齿动物模型中获得的结果可能不适合人类。由于流行病学研究将儿童时期邻苯二甲酸盐暴露与人类男性生殖发育障碍联系在一起，显然有必要对灵长类动物模型进行研究，正如NTP-CERHR DEHP生殖和发育毒性专家小组所强调的那样。在这个修订的探索性项目中，我们建议利用我们实验室开发的一种新的灵长类睾丸组织异种移植系统来研究DEHP和DBP对未成熟恒河猴睾丸成熟和睾丸功能的影响。具体目标1将检验这样一种假设，即暴露于与环境相关的浓度的DEHP或DBP将对睾丸体细胞功能和生殖细胞发育产生不利影响。具体地说，婴儿和幼年猴子的睾丸组织将被异位移植到老鼠宿主上，并暴露在不同剂量的DEHP或DBP中3个月。在不同的时间点，将比较治疗组织和对照组织中支持细胞的成熟、间质细胞的类固醇生成功能以及外源性促性腺激素诱导的生殖细胞分化，以评估慢性邻苯二甲酸盐暴露的潜在影响。特定目标2将研究邻苯二甲酸盐对婴儿灵长类睾丸毒性的机制。邻苯二甲酸盐在幼猴睾丸组织中诱导的全球基因表达模式的变化将通过微阵列分析进行评估，并通过RT-PCR进行确认。将特别关注与类固醇合成有关的基因的差异表达。这一探索性项目的成功完成将提供对邻苯二甲酸酯敏感性的洞察，表征对睾丸体细胞成熟的影响，并开始阐明邻苯二甲酸酯在未成熟灵长类睾丸中毒性的分子机制。拟议项目的结果将为未来对发育中的灵长类动物进行的研究提供基础。公共卫生相关性：啮齿动物模型通常被用来研究疑似生殖毒物，如邻苯二甲酸盐，对未成熟的人类睾丸的潜在影响，但物种特定的生殖器官新陈代谢和敏感性的差异可能不会使它们成为理想的模型系统。虽然对灵长类动物的研究更可能适用于人类，但它们往往成本高昂，伦理限制。在这项研究方案中，我们描述了一种新的系统，在该系统中，将灵长类睾丸组织移植到小鼠体内，以研究在灵长类动物中生殖邻苯二甲酸酯的毒性机制，而不需要在灵长类动物中进行广泛的实验。