汞的生殖毒性和发育毒性

本文综述了汞对雄性及雌性动物的生殖毒性 ,汞的胎盘及哺乳毒性、汞对胚胎和出生后动物发育的影响。汞能降低雄性鼠类及鹌鹑的交配能力 ,破坏鸭的睾丸间质细胞及精母细胞 ,并能破坏禽类的蛋壳结构而影响其生殖功能。汞不仅能通过胎盘途径 ,而且能经过哺乳途径进入胎儿体内 ,从而引起神经损伤等病变。汞能抑制蝌蚪的正常变态 ,引起动物胚胎被吸收或胚胎死亡 ,也可以导致胎儿腭裂、四肢缺失及脑部畸形。接触甲基汞的雄性小鼠对其第二代仔鼠的发育毒性比第一代更显著。     

牛膝多糖对炔雌醚致大鼠生精损伤的保护作用研究

为研究牛膝多糖对炔雌醚(Quinestrol)致雄性大鼠生殖损伤的保护作用,以20只8周龄成年雄性SD大鼠为研究对象。随机分为4组,分别进行炔雌醚与牛膝多糖处理。试验结束后,取睾丸、附睾、精囊腺和前列腺称重,取精子检测品质,测定睾丸抗氧化酶活性并观察睾丸形态与组织结构,检测Tunel表达。结果表明,炔雌醚引起大鼠生殖器官重量减少,形态萎缩,组织结构异常,精子数量和品质下降,抗氧化酶活性降低;Tunel表达增加。而炔雌醚+牛膝多糖处理组睾丸抗氧化酶活性升高,Tunel表达减少,降低精子畸形、提高精子数量和品质,缓解生精小管损伤,提高生殖器官重量,最终改善雄性大鼠生殖功能。与对照组相比,单独牛膝多糖处理组睾丸抗氧化酶活性、组织结构和精子质量均有一定程度提高。综上表明,牛膝多糖有效抑制了炔雌醚对生殖功能的破坏作用,对雄性生殖功能具有改善作用。     

维生素D对雄性动物生殖的影响

近来的一种论点就认为维生素D与雄性动物生殖能力有关。本文就维生素D对雄性动物生殖的影响做简要综述。     

镉对雄性动物生殖功能影响的研究进展

雄性生殖系统对镉较为敏感,镉可损伤雄性动物的精巢组织,包括睾丸中的各级生精细胞、类固醇分泌细胞、类固醇激素和酶水平等,从而降低精子质量、受精率和繁殖率,导致雄性动物生殖功能受到影响。镉对雄性性腺的毒性效应是镉与动物体相互作用的结果,在综述镉对雄性生殖系统影响的同时,进一步分析了镉可能对雄性性腺产生的毒性机制,以及镉在导致雄性性腺产生毒性效应的同时,所引起动物机体迅速启动一类应激蛋白即金属硫蛋白（metallothionein,MT）的应答反应,以保护机体免受镉的损伤。     

猪雄性生殖干细胞的分离纯化

 为了建立猪雄性生殖干细胞的分离纯化方法,以1~2周龄长白猪睾丸组织为材料,采用差异贴壁法和曲细精管培养法对猪雄性生殖干细胞进行分离纯化。结果表明：双酶消化-差异贴壁法和曲细精管培养法均能获得高活力的猪雄性生殖干细胞,但后者的富集效果较好,可以达到40.7%,前者的富集效果为 36.9%。差异贴壁法和曲细精管培养法具有操作简单、回收细胞纯度高等优点,可应用于猪雄性生殖干细胞的分离纯化。     

睾丸支持细胞的功能、分离纯化及鉴定研究进展

支持细胞对维持精子形成过程中的微环境起决定作用,它可以通过分泌功能、细胞间连接形成的血睾屏障功能以及吞噬功能等来促进精子的形成过程,其发育异常会导致不同程度的雄性生殖缺陷。基于支持细胞在雄性动物生殖过程中的作用,体外培养高纯度支持细胞可成为研究睾丸两大核心功能-精子发生和性激素分泌功能相关调节机制重要的细胞模型。此外,体外培养睾丸支持细胞也可作为生殖毒理学等新兴热点领域的细胞模型,为评估和研究环境因素对雄性生殖的影响提供便利。因此,作者系统地归纳、总结了目前关于动物支持细胞生物功能的研究及常用的体外分离纯化、培养及鉴定方法,以期为利用动物支持细胞开展雄性生殖领域的研究提供参考。     

雄性恒河猴生殖功能的季节性变化

采用随机抽样法和放射免疫测定法 ,分析了雄性恒河猴在不同季节的体重、睾丸容积、射精量、促卵泡刺激素(FSH)、促黄体生成素 (L H)和睾酮的变化情况。试验结果显示 ,雄性恒河猴的体重、睾丸容积和射精量的变化受季节因素的影响。在非生殖季节 ,雄性恒河猴的 FSH、L H和睾酮分泌水平明显偏低。在生殖季节 ,雄性恒河猴的 FSH、L H和睾酮分泌水平显著升高。揭示雄性恒河猴的生殖功能存在季节性变化     

雄性哺乳动物生殖系统对高原环境的适应及调控机制

高原生态因子中的光照、温度、高海拔低氧等是制约雄性动物生殖、发育的关键因素,对哺乳动物的生殖机能产生特殊的影响;而哺乳动物对高海拔环境有其独特的适应方式及调控机制。作者就哺乳动物雄性生殖系统对高原环境的适应及细胞因子调控等方面的研究进行了综述。     

犬的前列腺脓肿的诊断与治疗

前列腺疾病是一种可严重危害雄性动物生殖泌尿系统的综合症,它包括前列腺脓肿、前列腺增生、前列腺囊肿和前列腺癌.在犬科动物中前列腺疾病有较高的发病率,这引起了兽医界的广泛关注.     

锌与动物生殖的关系

从锌与雄性动物生殖、与雌性动物生殖,以及锌影响动物生殖机能的可能机制和锌的添加量四方面综述了锌与动物生殖的关系。     

Epigenetic mechanisms in the actions of endocrine-disrupting chemicals: gonadal effects and role in female reproduction

There is a heightened interest and concern among scientists, clinicians and regulatory agencies as well as the general public, regarding the effects of environmental endocrine-disrupting chemicals (EDCs). In this review, we identify the main epigenetic mechanisms and describe key ovarian processes that are vulnerable to the epigenetic actions of EDCs. We also provide an overview of the human epidemiological evidence documenting the detrimental effects of several common environmental EDCs on female reproduction. We then focus on experimental evidence demonstrating the epigenetic effects of these EDCs in the ovary and female reproductive system, with an emphasis on methoxychlor, an organochlorine pesticide. We conclude the review by describing several critical issues in studying epigenetic effects of EDCs in the ovary, including transgenerational epigenetic effects.     

Consequences of endocrine disrupting chemicals on reproductive endocrine function in birds: establishing reliable end points of exposure

It has been difficult to establish reliable indices of exposure to endocrine disrupting chemicals (EDCs) appropriate for a variety of avian species because of a vast array of reproductive strategies. Data from mammals, reptiles and fish provide insight on likely mechanisms of action for EDCs. However, many of the effects of EDCs are weaker than the actions of the native hormones, making it difficult to assess adverse effects in domestic and wild birds. It is clear that differential sensitivity to EDCs exists across species, due to the timing and mode of exposure, compound toxicity and age of the individual. Our studies on EDCs are conducted in the quail model system, with focus on reproductive endocrine, neuroendocrine and behavioral responses. Studies have included EDC exposure, either by egg injection or via diet. Results from egg injection studies showed the following: (1) estradiol administered by embryonic day 12 demasculinized male sexual behavior, altered hypothalamic neurotransmitters and reduced hen day production and fertility in a dose dependent fashion, (2) methoxychlor (MXC) or vinclozolin impaired male sexual behavior in adult quail and (3) DDE exposure impaired reproductive and immune related end points. Two-generation studies were conducted on Japanese and northern bobwhite quail with dietary methoxychlor (MXC) exposure (0, 5 and 10 ppm) beginning in adults (P1), continuing in their offspring (F1), with F2 offspring raised on control diet. MXC exposure impaired male sexual behavior, hypothalamic catecholamines and plasma steroid hormones. Moreover, MXC exposure had reproductive consequences observable at both the lower and higher doses of MXC in F1 and F2 generations. These data demonstrate that embryonic EDC exposure interferes with sexual differentiation of neural systems that direct reproduction.     

Effects of Endocrine Disrupting Compounds in Animal Feed on Reproductive Health in Farm Animals*Euroconference Wageningen, The Netherlands, 20–22nd November 1998

This Euroconference was a follow-up to the Euroconference held in Halle, April 1997. The programme of the conference in Halle had an exploratory character with respect to accumulation of endocrine disrupting compounds (EDCs) in the environment and in animal tissues and their effects on animal physiology and reproduction. Many questions arose from the first Euroconference, such as: What are biologically meaningful levels of environmental contamination? Is there a risk for farm animals’ health and reproduction? What assays are available and which are the most appropriate to be used? These questions formed the basis for the programme of the second Euroconference held in Wageningen in November 1998. Taking these questions into consideration, the programme of the Wageningen Euroconference was divided into four main topics. In the first session an overview was given on sources and levels of EDCs in the environment. The second session addressed chemical nature and metabolism of EDCs including phytoestrogens. In the third session the effects of EDCs on ovarian function and embryo development were discussed and in the last session the advantages and disadvantages of different in vivo as well as in vitro assays were debated.     

Risk assessment of endocrine-active compounds in feeds

As a key element of the 'farm-to-fork' approach, an assessment of the safety of feed components should consider major long-term toxicological hazards, such as endocrine disrupting chemicals (EDCs). In this review, attention is given to endocrine-modulating trace elements (such as iodine and trivalent chromium) and their potentially sensitive subgroups as nutritional feed additives from the standpoint of farm animal safety and consumer exposure. Feedstuffs can be a major vehicle for persistent EDCs, such as polychlorinated biphenyls, and potential risks include fish farming and ruminants grazing in polluted areas. Limited data still exist on the feed-to-food transfer of other EDCs, such as brominated flame retardants. EDCs of vegetable origin (e.g. zearalenone and isothiocyanates) can have a greater adverse impact on farm animals than environmental xenobiotics but the risk of carry-over to consumers appears low. Topics for further research are suggested, including the need for more refined exposure data, characterization of biomarkers for long-term effects, xenobiotic-nutrient interactions and the search for novel feed ingredients that are less vulnerable to contamination.     

Impact of Endocrine‐Disrupting Chemicals on Reproductive Function in Zebrafish (Danio rerio)

The prevalence of endocrine‐disrupting chemicals (EDCs) in the aquatic environment has been associated with the wide detection of alterations in the development and physiology of vertebrates. Zebrafish, as a model species, has been extensively used in toxicological research. In this review, we focus on recent published evidence of the harmful effects of EDCs on reproductive function in zebrafish, including skewed sex ratio, immature gonads, diminished sexual behaviour, decreased sperm count, reduced spawning and fertilization. These impairments mostly result from disruption to sex‐steroid hormones induced by endocrine disruptors. We also discuss other effects of exposure to EDCs. In EDC exposure research, despite incomplete assessments of altered gonad histopathology and sexual behaviour, these present potential effective biomarkers or pathways for evaluating the reproductive function in zebrafish on EDC exposure. To date, the pernicious effects of some EDCs on the reproductive performance in laboratory zebrafish are well understood; however, similar alterations remain for further determination in wild‐type fish and more kinds of EDCs. More studies should be performed under established scientific regulatory criteria to investigate the impact of EDCs on reproduction in zebrafish. Moreover, further research is required to explain the definite mechanism of sexual differentiation, which helps in understanding the shift of sexual phenotype with EDC exposure.     

Are Endocrine Disrupting Compounds a Threat to Farm Animal Health,Welfare and Productivity?

Contents The sources and characteristics of endocrine disrupting compounds (EDCs) are reviewed and discussed with respect to their potential effects on farm animal health, welfare and productivity. The importance of certain properties of these compounds in relation to the expression of their biological effects is addressed together with potential routes of exposure. It is concluded that little is known of factors affecting the tissue concentrations of EDCs in farm animals, the concentrations that are required to perturb physiological function in these species, the effects of prolonged exposure to low doses, the effect of cocktails of EDCs and other pollutants or the responses of specific organs and physiological systems that are affected by EDCs. Much of the available information pertaining to EDCs is derived from epidemiological studies of wildlife species and from laboratory animal studies and while these studies have significant limitations, they are considered to be valuable indicators of potential effects in farm animal species. The results of such studies, together with the small amounts of data from studies of ruminants, indicate that there may be significant effects of exposure to environmental levels of EDCs on farm animal health, even although effects are not generally apparent in practice, at this time.     

17α-甲基睾酮对稀有鮈鲫体内激素水平的影响

环境内分泌干扰物（EDCs）对动物和人的健康有一定的危害作用,很大一部分环境内分泌干扰物最终都进入到了水环境中,对水生生物的生殖、内分泌等系统造成损伤。以稀有鮈鲫作为毒性试验材料,选择具有代表性的雄激素17α-甲基睾酮（MT）作为研究对象,采用酶联免疫法（ELISA）研究MT处理7 d对稀有鮈鲫体内雌二醇（E2）、睾酮（T）和11-酮基睾酮（11-KT）含量的影响。结果显示,经MT处理7 d后,雌鱼体内的E2、T和11-KT含量均极显著高于对照组（P〈0.01）,而雄鱼体内的E2、T和11-KT含量均极显著低于对照组（P〈0.01）。     

Is exposure to endocrine disrupting compounds during fetal/post-natal development affecting the reproductive potential of farm animals?

Concerns have been raised about the potential adverse effects on reproductive health and immune status of farm animals following exposure to a range of natural and synthetic environmental compounds that disrupt normal hormonal actions. These compounds range from natural plant oestrogens (e.g. genistein, coumesterol) and mycoestrogens (e.g. Aflatoxins, zearalenone) to growth promoting pharmaceuticals (e.g. trenbolone acetate, melengastrol acetate) to chemicals spread in water, sewage sludge or the atmosphere such as detergents and surfactants (e.g. octylphenol, nonylphenol), plastics (e.g. bisphenol-A, phthalates), pesticides (e.g. methoxychlor, dieldrin, DDT) and industrial chemicals (e.g. PCB, TCDD). These compounds are commonly termed 'endocrine disrupting compounds' (EDCs) or 'endocrine disruptors' due to their ability to act as either hormone agonists or antagonists or the ability to disrupt hormone synthesis, storage or metabolism. A similar group of compounds are called 'immunotoxicants' and are thought to affect the immune system mainly by disrupting B and T cell homeostasis. As more studies are performed it is becoming clear that many compounds can directly or indirectly affect both the endocrine and immune systems. The susceptibility of target tissues is related to the stage of development, the cumulative exposure dose and the immune status of the individual. While some of the effects of the EDCs on the endocrine and immune systems are quite distinct, many are subtle and identifying the causative agent from the vast array of environmental challenges including EDCs, nutrition, temperature, etc. can be problematic. Identifying the causative agent is confounded by the possibility that effects that are observed in the adult may be due to exposure to EDCs during fetal life. This has major implications for the determination of universal end-point measurements to assess exposure to EDCs in farm animals.     

The combined effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin and the phytoestrogen genistein on steroid hormone secretion,AhR and ERβ expression and the incidence of apoptosis in granulosa cells of medium porcine follicles

Low doses of endocrine disrupting chemicals (EDCs) used in combination may act in a manner different from that of individual compounds. The objective of the study was to examine in vitro effects of low doses of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; 100 pM) and genistein (500 nM) on: 1) progesterone (P₄) and estradiol (E₂) secretion (48 h); 2) dynamic changes in aryl hydrocarbon receptor (AhR) mRNA and protein expression (1, 3, 6, 24 and 48 h); 3) dynamic changes in estrogen receptor β (ERβ) mRNA and protein expression (1, 3, 6, 24 and 48 h); and 4) induction of apoptosis in porcine granulosa cells derived from medium follicles (3, 6 and 24 h). TCDD had no effect on P₄ or E₂ production, but potentiated the inhibitory effect of genistein on P₄ production. In contrast to the individual treatments which did not produce any effects, TCDD and genistein administered together decreased ERβ and AhR protein expression in granulosa cells. Moreover, the inhibitory effect of TCDD on AhR mRNA expression was abolished by genistein. The treatments did not induce apoptosis in the cells. In summary, combined effects of low concentrations of TCDD and genistein on follicular function of pigs differed from that of individual compounds. The results presented in the current paper clearly indicate that effects exerted by low doses of EDCs applied in combination must be taken into consideration when studying potential risk effects of EDCs on biological processes.