纳米二氧化钛暴露致小鼠生殖毒性及其基因表达的变化

发布时间：2018-04-28 01:58

本文选题：纳米二氧化钛 + 小鼠　；参考：《苏州大学》2013年博士论文

【摘要】：纳米氧化钛(TiO_2)是目前国际上生产量最大，在工业、医药卫生、日用化妆品、食品以及环保方面应用最广泛的一种纳米材料。然而随着纳米材料的广泛应用，包括纳米TiO_2在内的纳米材料的潜在环境卫生和职业卫生安全越来越受到人们的高度关注，已成为研究热点。2012年初，美国国家科学院国家研究理事会发布了“工程纳米材料的环境、健康与安全性的研究战略(A Research Strategy forEnvironmental, Health, and Safety Aspects of Engineered Nanomaterials)”报告，提出需要制定整体的研究计划，避免纳米技术快速发展带来的潜在风险(http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=13347)。近年来研究，不仅证实纳米TiO_2暴露可引起动物肝、脾、肺的损伤，尤其是肾和脑的损伤，，而且阐明了相应的损伤机制,而肾和脑这两种器官又与生殖系统的功能密切相关。人们长期使用含有纳米TiO_2的化妆品及长期生活或工作在暴露有纳米颗粒的环境下(如生产车间的工人），其纳米颗粒通过皮肤渗透、呼吸和消化系统而进入体内，并可能通过血液循环、血睾屏障在卵巢和睾丸中积累，进而导致生殖系统损伤。但纳米TiO_2暴露对生殖系统的损伤及其机制研究尚不够深入。因此开展纳米TiO_2生殖系统毒性的研究具有非常重要的理论意义和实际意义。鉴于此，本论文以10mg/kg BW的纳米TiO_2（锐钛型5nm）连续灌胃处理雌性和雄性小鼠90天，对其生殖系统的损伤进行了研究；同时结合基因芯片技术深入研究了生殖系统损伤多基因共同作用的分子机制。本研究可为纳米材料长期暴露引起生殖系统的毒性评估提供重要的理论依据。论文结果如下： (1)用纳米TiO_2(10mg/kg)对雌性小鼠持续灌胃90天后，研究了雌性小鼠卵巢的损伤和卵巢基因表达特征。结果显示纳米TiO_2颗粒能够进入卵巢中积累并且导致卵巢的损伤如卵巢萎缩，初级卵泡和次级卵泡发育障碍，卵巢细胞的不规则排列和卵泡腔的形状不规则。纳米TiO_2颗粒也可进入卵巢细胞甚至细胞核，进而导致细胞凋亡。纳米TiO_2颗粒暴露造成了卵巢组织钙、钠、钾和锌金属元素的含量增加，而镁、铜和铁金属元素的含量下降。纳米TiO_2颗粒暴露导致了性激素的不平衡，如血清孕酮、促黄体生成素、睾酮和促卵泡激素的水平降低，雌二醇的浓度增加，进而引起生育力下降，如交配率、怀孕率、产仔数都显著下降及子代生长发育减慢。同时纳米TiO_2颗粒暴露引起了卵巢严重的氧化性损伤，如ROS大量积累和DNA氧化水平增加。微阵列分析显示，纳米TiO_2处理的小鼠卵巢组织中有223个已知功能基因上调(diffscore≥13, p0.05)，65个已知功能基因下调(diffscore-13, p0.05)。在本研究中，卵巢的差异基因的功能分别涉及细胞分化、免疫炎症反应、离子运输、代谢过程、氧化应激反应、内固醇代谢、凋亡、信号转导、信号通路、转录、运输等。尤其是与内固醇和性激素代谢过程有关的Akr1c18、Cyp17a1和Lgmn显著上调，这些基因的过表达引起雌二醇浓度上升，以及孕酮、促黄体生成素和睾酮浓度下降，进而抑制卵泡发育和降低雌性小鼠的生育力。另外，纳米TiO_2颗粒暴露后导致卵巢Cyp17a1的表达显著增加也可促进雌二醇的生物合成。 (2)分析了10mg/kg纳米TiO_2钛颗粒持续90天灌胃雄性小鼠后生殖毒性和基因表达谱变化。结果表明纳米TiO_2颗粒能够通过血睾屏障在睾丸中沉积，并且导致睾丸的损伤和细胞凋亡，如生精管空泡化、生精层的厚度减小，睾丸细胞的不规则排列和支持细胞的空泡化；附睾尾部的精子发生异常的变化，如总的精子浓度和精子活力下降，精子畸形率显著增加，精子损伤严重如头尾断裂；雄性小鼠的生育力显著下降，如低的交配率、妊娠率和少的产仔数。纳米TiO_2的暴露导致睾丸组织中钙和铁的含量下降，锌含量显著增加。同样，纳米TiO_2暴露也造成性激素的不平衡，如雌二醇和孕酮显著增加，而促卵泡激素、促黄体生成素和睾酮水平显著下降。微阵列分析显示与对照比较，纳米TiO_2处理组的小鼠睾丸组织有155个基因明显上调(diffscore≥13, p0.05)，100个基因明显下调(diffscore-13,p0.05)。对已知功能的差异基因分类，表明差异基因的功能涉及的范畴有精子发生、内固醇代谢过程、凋亡、免疫、细胞分化、氧化应激反应、氧化还原活性、激素活性、离子运输等。尤其是Spata19、Tdrd6和Tnp2表达的显著下调直接与精子发生的抑制有关，而Cyp2e1、Mvd、Sc4mol和Srd5a2与内固醇代谢有关,Cyp2e1表达下调，Mvd、Sc4mol和Srd5a2表达上调。
[Abstract]:Nanoscale titanium oxide (TiO_2) is the most widely used nano material in the field of industry, medicine and health, daily cosmetics, food and environmental protection. However, with the wide application of nanomaterials, the potential of nanomaterials, including nano TiO_2, is becoming more and more popular in environmental hygiene and occupational health. At the beginning of.2012, the National Research Council of the National Academy of Sciences issued the "A Research Strategy forEnvironmental, Health, and Safety Aspects of Engineered Nanomaterials) report, and proposed the need to develop the overall research. To avoid the potential risk (http://www8.nationalacademies.org/onpinews/newsitem.aspx? RecordID=13347) from the rapid development of Nanotechnology (http://www8.nationalacademies.org/onpinews/newsitem.aspx? RecordID=13347). In recent years, it has been studied not only that nano TiO_2 exposure can cause damage to animal liver, spleen and lung, especially kidney and brain damage, but also elucidate the corresponding damage mechanism, while the kidney and brain are two The organ is also closely related to the function of the reproductive system. People have long used cosmetics containing nano TiO_2 and long life or work in the environment of exposed nanoparticles, such as workers in the production workshop, whose nanoparticles enter the body through the skin infiltration, respiration and digestive systems, and may circulate through the blood and the blood testis barrier in the body. The accumulation of the ovary and testicle leads to the damage of the reproductive system, but the research on the damage and mechanism of the reproductive system by nano TiO_2 exposure is not enough. Therefore, it is of great theoretical and practical significance to study the toxicity of the reproductive system of the nano TiO_2 reproductive system. In view of this, this article uses the 10mg/kg BW nano TiO_2 (anatase 5nm) continuously. The female and male mice were treated with gavage for 90 days, and the damage of their reproductive system was studied. At the same time, the molecular mechanism of the multigene interaction of reproductive system injury was studied by gene chip technology. This study could provide important theoretical basis for the assessment of the toxicity of the reproductive system by the long-term exposure of nanomaterials.
The results of the paper are as follows:
(1) the ovarian damage and ovarian gene expression in female mice were studied after 90 days after continuous gavage of female mice with TiO_2 (10mg/kg). The results showed that the nano TiO_2 particles could accumulate in the ovary and cause ovarian damage, such as ovarian atrophy, primary follicle and secondary follicle development disorder, irregular arrangement of ovarian cells and the abnormal arrangement of ovarian cells. The shape of the follicle cavity is irregular. Nanoscale TiO_2 particles can also enter ovarian cells and even nuclei and lead to cell apoptosis. The exposure to nano TiO_2 particles causes the increase in the content of calcium, sodium, potassium and zinc metal elements in the ovarian tissue, while the content of magnesium, copper and iron elements is decreased. The exposure of nano TiO_2 particles leads to the imbalance of sex hormones. Such as serum progesterone, luteinizing hormone, testosterone and follicle stimulating hormone levels, the increase of estradiol, and the decrease of fertility, such as mating rate, pregnancy rate, litter size and progeny growth slowing. Meanwhile, the nano TiO_2 particle exposure causes severe oxidative damage to the ovary, such as the accumulation of ROS and DNA oxygen. Microarray analysis showed that there were 223 known functional genes up regulation (diffscore > 13, P0.05) and 65 known functional genes down regulation (diffscore-13, P0.05) in the mouse ovarian tissue treated with nanoscale TiO_2. In this study, the functional differentiation of the ovarian differential genes involved cell differentiation, immuno inflammatory response, ion transport, metabolism. Process, oxidative stress response, metabolism of sterol, apoptosis, signal transduction, signal transduction, signaling, transcription, transport, etc., especially Akr1c18, Cyp17a1 and Lgmn associated with steroid and sex hormone metabolism, the overexpression of these genes increases the concentration of estradiol, and progesterone, luteinizing hormone and testosterone, and then inhibition of eggs. Bubbles develop and reduce the fertility of female mice. In addition, after exposure to nano TiO_2 particles, the expression of Cyp17a1 in the ovary is increased significantly and the biosynthesis of estradiol can also be promoted.
(2) the reproductive toxicity and gene expression profiles of 10mg/kg nanoscale TiO_2 titanium particles were analyzed after 90 days of gastric perfusion in male mice. The results showed that the nano TiO_2 particles could be deposited through the blood testis barrier in the testis, and caused the damage and apoptosis of the testis, such as the vacuolation of spermatogenic tube, the decrease of the thickness of spermatogenic layer, and the irregular row of the testicular cells. The vacuolization of columns and supporting cells; abnormal changes in spermatogenesis in the tail of the epididymis, such as the total sperm concentration and sperm motility, a significant increase in sperm abnormality, and severe sperm damage such as the head and tail fracture; the fertility of male mice decreased significantly, such as low mating rate, pregnancy rate and litter size. The exposure to nano TiO_2 led to the testicles. The content of calcium and iron in the tissue decreased and the zinc content increased significantly. Similarly, TiO_2 exposure also resulted in the imbalance of sex hormones, such as estradiol and progesterone, while follicle stimulating hormone, luteinizing hormone and testosterone levels decreased significantly. Microarray analysis showed that there were 155 mice in the nano TiO_2 treatment group compared with the control group. The genes were significantly up-regulated (diffscore > 13, P0.05), and 100 genes were obviously down regulated (diffscore-13, P0.05). The differential gene classification of known functions indicated that the function of the differential genes involved spermatogenesis, sterol metabolic process, apoptosis, immunization, cell differentiation, oxidative stress reaction, redox activity, hormone activity, ion transport, etc. In particular, the significant down-regulation of Spata19, Tdrd6 and Tnp2 is directly related to the inhibition of spermatogenesis, while Cyp2e1, Mvd, Sc4mol and Srd5a2 are related to the metabolism of sterol, the expression of Cyp2e1 is down, Mvd, Sc4mol and Srd5a2 are up-regulated.

【学位授予单位】：苏州大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：R114

【参考文献】