Effects of 17beta-estradiol and tamoxifen on the selenoprotein phospholipid hydroperoxide glutathione peroxidase (PHGPx) mRNA expression in male reproductive organs of rats

The selenoprotein phospholipid hydroperoxide glutathione peroxidase (PHGPx) is highly expressed in testes under gonadotropin control. The expression patterns of PHGPx mRNA by 17beta-estradiol (E2) as an estrogen and tamoxifen (Tam) as an estrogen antagonist were investigated in the reproductive organs of male rats. Twelve-week-old male Sprague-Dawley rats were subcutaneously injected with E2 (7.5 microg/kg/day) or Tam (5 mg/kg/day) for 1 week. The E2 treatment significantly increased the levels of PHGPx mRNA in both testes and prostates, whereas the Tam treatment significantly decreased the levels of PHGPx mRNA, compared to the vehicle control (p<0.01). The treatment with E2 or Tam slightly decreased the levels of PHGPx mRNA in epididymides. In histopathological examination, severe vacuolization and depletion of germ cells in the seminiferous tubules, cell debris in the tubular lumen, and mild proliferative changes in interstitial tissues were observed in the testes of Tam-treated rats, whereas only mild spermatogonial proliferation was observed in the seminiferous tubules of E2-treated rats. There were no typical histopathological changes in the epididymides of any of the laboratory rats but mild epithelial proliferation in the prostates of E2- and Tam-treated rats. These results suggest that PHGPx mRNA expression may be influenced by estrogen in the male reproductive organs.     

Impact of endocrine disrupting chemicals on reproduction in Japanese quail

Many environmental contaminants can interact with the endocrine system, thereby potentially disrupting the reproductive fitness of individuals. In avian species, the egg-yolk is a major route for excretion of lipophilic compounds by the adult female bird and embryos are exposed to contaminants that have been deposited in the eggs. The reproductive and neuroendocrine system of Japanese quail undergoes sexual differentiation during embryo development. The phenotypic sex, including sex-specific adult behavior, is hormonally imprinted already before hatching. The sexual differentiation of the brain in quail is sensitive to estrogens and the presence of estrogen results in a female phenotype. The relatively low concentration of estrogens in male embryos, on the other hand, results in a male behavioral phenotype. The behavior of male quail can be demasculinized by estrogen exposure during the period of sexual differentiation, and estrogen-exposed males are not able to display a male-typical behavior as adults. Also, differentiation of the reproductive organs is sensitive to hormones during embryogenesis, and an excess of estrogens can for instance induce persistent morphological changes in the reproductive organs of females. Our research has focused on effects in adult birds after embryonic estrogen exposure. We have studied sexual behavior and other reproductive variables in adult quail after in ovo injection of known and suspected estrogenic compounds. Synthetic estrogens and insecticides, such as o,p'-DDT altered the development of the neural system and resulted in demasculinization of male quail. In females, o,p'-DDT caused morphological changes of the oviduct and egg laying was reduced. Our studies suggest that the neural system and the female reproductive system of avian embryos are very sensitive to the effects of chemicals with estrogenic activity.     

Effects of ginsenosides on organogenesis and expression of glutathione peroxidase genes in cultured rat embryos

Ginseng has been extensively used around the world for several thousand years as a food or drug. However, recently, several reports have indicated that the organogenesis of cultured embryos is inhibited by treatment with ginsenoside, the principal component of ginseng. In this study, we evaluated the morphological changes of embryos and the gene expression patterns of antioxidant enzymes, 3 types of glutathione peroxidases [GPx; cytosolic (cGPx), plasma (pGPx) and phospholipid hydroperoxide (phGPx) forms], in cultured rat embryos (embryonic days 9.5-11.5) exposed to ginsenosides Rb1, Rg1, Re and Rc at levels of 5, 50 and 100 microg/ml. With regard to total morphological scores, no significant differences were noted in the embryos exposed to all doses of ginsenosides, with the exception of 50 microg/ml of Rc. In the cultured embryos exposed to Rg1, a majority of the developmental parameters were normal, but growth of the hind- and mid- brains and the caudal neural tube was significantly increased compared with that observed in the control group (P<0.05). Furthermore, Rc significantly enhanced the growth of a variety of developmental parameters in the cultured embryos, with the exception of the hindlimbs. According to the results of our semiquantitative RT-PCR analysis, the levels of cGPx and phGPx mRNA in the cultured embryos were unaffected by treatment with the ginsenosides. However, the levels of pGPx mRNA increased significantly in the embryos treated with ginsenosides Re, Rc and Rb1 compared with the control group (P<0.05). These findings indicate that ginsenosides may exert a stimulatory effect on the growth of embryos via differential expression of GPx genes.     

Effect of chemicals on glutathione peroxidase of chick liver

Chick liver glutathione peroxidase activity was separated into selenium-dependent and selenium-independent enzyme fractions and the effects of chemicals on the activities of each fraction were examined. Clofibrate induced the selenium-dependent enzyme, while phenobarbital, butylhydroxyanisole and trans-stilbene oxide elevated selenium-independent peroxidase activity. A third enzyme, which showed glutathione peroxidase activity toward both hydrogen peroxide and cumene hydroperoxide, was found.     

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.     

环境内分泌干扰物对动物繁殖机能的干扰作用及其机制

环境内分泌干扰物 (endocrine disrupting chem icals,ED-Cs)是指存在并积蓄在环境中 ,结构类似动物体内激素 ,可引起人和动物的内分泌发生紊乱的化学物质 ,也称环境激素。内分泌干扰物不同于其他环境污染物 ,它一旦进入动物体内 ,不仅可以导致其自身内分泌系统异常 (如性激素和甲状腺激素分泌障碍 )、生殖器官异常 (如精子减少、睾丸癌、乳腺癌 )、神经系统异常 (如智能低下、多动症 )和免疫系统异常 (过敏性疾病增加 )。同时 ,因其难分解和强蓄积性 ,可进而影响到下一代和食物链中的其他生物体。因此 ,内分泌干扰物的研究关系到动物乃至…     

Differential expression of gastrointestinal glutathione peroxidase (GI-GPx) gene during mouse organogenesis

Gastrointestinal glutathione peroxidase (GI-GPx) is an antioxidant enzyme that has been known to be restricted to the gastrointestinal tract in rodents. In an effort to determine the expression pattern of GI-GPx mRNA during organogenesis, quantitative real-time PCR and in situ hybridization for GI-GPx mRNA were conducted in whole embryos or each developing organ of mice. GI-GPx mRNA was expressed more abundantly in the extraembryonic tissues, including placenta than in embryos on embryonic days (EDs) 7.5-18.5 (P < 0.05). When compared with the expression levels of cytosolic GPx (cGPx) mRNA, GI-GPx mRNA levels were low in the embryos, but relatively high in the extraembryonic tissues (P < 0.05). According to the results of whole mount in situ hybridizations, GI-GPx mRNA was principally expressed in the ectoplacental cone, neural tube and fold, and primitive heart at EDs 7.5-8.5. At EDs 9.5-12.5, GI-GPx mRNA was abundantly expressed in nervous tissues such as the telencephalon, mesencephalon and dorsal neural tube and was also detected in the forelimb and hindlimb at EDs 10.5-12.5. In the sectioned embryos after ED 13.5, GI-GPx mRNA levels were high in the cerebral cortex, metanephric corpuscle, pancreatic ducts, surface epithelia of the skin, inner ear, and nasal conchae, gastrointestinal tract, liver, urinary bladder, airway passages of lung, and whisker follicles. These findings indicate that GI-GPx is not only spatiotemporally expressed in a variety of embryonic organs during organogenesis but also may perform a mutual compensatory role with the cGPx in the protection of embryos and extraembryonic tissues against the reactive oxygen species generated in ontogenetic periods.     

捻转血矛线虫谷胱甘肽过氧化物酶体外对山羊外周血单核细胞功能的影响

本文探讨了捻转血矛线虫的谷胱甘肽过氧化物酶(HC29)体外对山羊外周血单核细胞(PBMCs)功能的影响。颈静脉采取无捻转血矛线虫感染的山羊血液,分离单核细胞后加入终浓度为5μg/mL的HC29重组蛋白进行体外培养,通过免疫荧光抗体技术观察重组蛋白与单核细胞的结合情况;HC29刺激山羊外周血单核细胞,用qPCR技术测定各试验组单核细胞中IL-2、IL-4、IL-10、IL-17、IFN-γ和TGF-βmRNA的转录水平;重组蛋白刺激单核细胞,采用CCK-8法测定细胞的增值情况;将重组蛋白与巨噬细胞共培养,测定巨噬细胞吞噬和分泌NO的情况。结果表明,重组HC29能够与外周血单核细胞结合并刺激细胞因子IL-10和IFN-γ的表达水平显著提高(P<0.01),能够引起单核细胞增值(P<0.01),巨噬细胞吞噬作用增强(P<0.01)和NO分泌增加(P<0.01)。结果表明HC29是捻转血矛线虫的一个重要抗原,主要诱导Th1类免疫反应。     

Ethanol decreases the expression of pituitary adenylate cyclase activating polypeptide in rat testes

The present study was designed to evaluate the effect of ethanol on pituitary adenylate cyclase activating polypeptide (PACAP) expression in adult rat testes. Ethanol (3 g/kg i.p., 15% v/v in saline) was administrated to adult male rats for 10 days. Using northern blot analysis, we elucidated the decrease of PACAP mRNA in rat testes by ethanol administration. The level of PACAP mRNA was decreased by 46.5% in testes of the ethanol-treated animals, compared to that of saline-treated animals. In particular, ethanol exposure decreased the expression of PACAP mRNA and protein in developing germ cells, which are sperm cell progenitors. Thus, our findings suggest that the decrease of PACAP in developing germ cells by ethanol administration may contribute to the suppression of male reproductive activity.     

纳洛酮对大鼠大脑皮质c-fos mRNA表达的影响

为研究纳洛酮对小型猪特异性麻醉剂(XFM)麻醉下大鼠大脑皮质c-fos mRNA表达的影响,探讨纳洛酮催醒XFM麻醉大鼠与大脑皮质c-fos基因的关系.将78只SD纯种大鼠随机分为空白对照组、XFM对照组、XFM+纳洛酮组、XFM+生理盐水组,采用实对定量PCR技术检测大脑皮质内c-fos mRNA表达量.结果表明,腹腔注射XFM后引起大鼠大脑皮质c-fos mRNA高效表达,各时期c-fos mRNA表达与空白对照组比较差异极显著(P＜0.01);纳洛酮注射后引起XFM麻醉大鼠大脑皮质c-fos mRNA表达量减少,与XFM对照组比较差异显著(P＜0.01或P＜0.05).结果提示,大脑皮质c-fos基因参与了纳洛酮颉颃XFM的麻醉作用,纳洛酮抑制XFM诱导大鼠大脑皮质c-fos基因表达,可能是纳洛酮催醒XFM麻醉大鼠的重要机理之一.     

还原型谷胱甘肽对肉鸡生长及血清IGF-1水平、组织IGF-1 mRNA表达的影响

9日龄黄羽雌性肉鸡1 000只随机分为A、B、C、D 4个组,每组设5个重复,每个重复50只。在A、B、C、D组的日粮中分别添加剂量为0、80、120、160mg/kg的还原型谷胱甘肽(GSH),饲养期84 d。观察GSH对肉鸡生长性能、血清类胰岛素生长因子1(IGF-1)、T3、T4水平以及组织IGF-1 mRNA表达的影响。结果表明,(1)添加GSH的鸡只血中GSH水平显著高于对照组(A组);(2)添加GSH的鸡只平均体质量和平均日增重均高于A组,其中B组显著高于A组;(3)添加GSH的鸡只血中IGF-1水平显著高于A组,血中T3水平明显升高,T4水平有升高趋势;(4)各试验组肝脏IGF-1 mRNA的表达水平有所增高,但不明显。35d时,C组胸肌组织的IGF-1 mRNA表达水平显著性高于A组。结果提示,肉鸡饲粮中添加GSH可增强肝脏IGF-1的分泌和肌肉组织IGF-1 mRNA的表达,血中IGF-1水平升高,而促进鸡只生长。     

Vimentin expression in testes of Arabian stallions

Reasons for performing study: Specific patterns of cytoskeletal filaments reflect a functional state of the cell. In testicular cells intermediate filaments (IFs) are of the vimentin type. Since it is known that Sertoli cells regulate the spermatogenic function in the male gonad, it became important to propose a system that could quantify the state of seminiferous tubular quality. To date, a Johnsen score system has never been used to equine testes. Objectives: To demonstrate the expression pattern of vimentin in testes of mature Arabian stallions and correlate its distribution with grade of seminiferous tubule impairment as indicated by a Johnsen score. Methods: For histological examination by the Johnsen method, routine haematoxylin‐eosin staining was used. Vimentin expression and its presence in testicular sections and testicular homogenates were detected by immunohistochemistry and western blot, respectively. Both analyses were performed qualitatively and quantitatively and further validated by ANOVA tests. Results: Distinct morphology of seminiferous tubules was found in testes harvested from 3 stallions. Vimentin in IFs was immunolocalised to the cytoplasm of Sertoli, Leydig and peritubular‐myoid cells. The intensity and pattern of the IFs staining was different in individual seminiferous tubules suggesting a correlation between vimentin expression and the severity of tubule degeneration. Qualitative results by immunohistochemistry and western blot were confirmed by further quantitative analyses. Conclusions: In equine testes, differential expression of vimentin was found to be correlated with the impairment of seminiferous tubules indicated by a decrease in Johnsen score. Potential relevance: The Johnsen score system may be a useful method to facilitate the identification of tubular alterations in the stallion testes. Combined histological and immunohistochemical approach may provide a detailed phenotypic classification of stallions with decreased fertility.     

Effects of endocrine disrupting compounds on the pathology and oestrogen receptor alpha and beta distribution in the uterus and cervix of ewe lambs

A number of chemicals have been classed as endocrine disrupting compounds due to their ability to mimic the actions of endogenous hormones in vivo and in vitro. The objective of this experiment was to determine the pathological changes and oestrogen receptor (ER) distribution in the cervix and uterus of prepubertal ovariectomised ewe lambs following exposure to a range of compounds with a predominantly oestrogenic effect. Lambs were exposed to diethylstilbestrol (0.175 mg/kg biweekly), bisphenol-A (3.5mg/kg biweekly) or octylphenol (3.5mg/kg biweekly) for 6 weeks. Following sacrifice, uterine and cervical tissue pathology was assessed. The endometrial and myometrial areas were quantified and the distribution of ERalpha and ERbeta assessed by immunohistochemistry. No differences were observed between control and octylphenol-exposed lambs in uterine gross pathology and histopathology. Uteri from bisphenol-A- and diethylstilbestrol-exposed lambs were heavier than both control and octylphenol-exposed lambs. In the bisphenol-A-exposed lambs, endometrial oedema accounted for a significant increase in the endometrial cross-sectional area over the other groups. Uteri from animals exposed to diethylstilbestrol showed variable pathology including oedema and cellular proliferation. Keratinisation of the cervical epithelium was observed in both bisphenol-A- and diethylstilbestrol-exposed lambs. Exposure to diethylstilbestrol and bisphenol-A was associated with a diffuse intracellular distribution of ERalpha and ERbeta in the uterine endometrium. This was in addition to the strong cytoplasmic staining of uterine epithelial cells and nuclear staining of specific sub-epithelial cells observed in all groups. We conclude that a 6-week exposure of lambs to bisphenol-A and diethylstilbestrol altered the uterocervical environment and has the potential to disrupt subsequent reproductive function. Pathological changes could not be detected in the uterus or cervix of lambs exposed to octylphenol.     

Assessment of blood glutathione peroxidase activity in the dromedary camel

Blood glutathione peroxidase (GSH-Px) levels in 709 normal dromedary camels (442 females and 267 males) were assessed in the Canary Islands. All animals were intensively reared, and three different nutritional systems were evaluated, depending on selenium content of the diet. Mean GSH-Px level in the total population was 288.5+/-157.2 IU x g(-1) Hb. Reference ranges were estimated and enzymatic activities below 51 IU x g(-1) Hb were considered inadequate. GSH-Px activities obtained in females (298.1+/-155.7 IU x g(-1) Hb) were significantly (P = 0.037) higher than in males (272.6+/-157.2 IU x g(-1) Hb). When age groups were compared, only males between 6 and 12 months old exhibited significantly lower mean GSH-Px (P = 0.006) than females. A high correlation (r = 0.88) between serum selenium concentration and blood GSH-Px activity was estimated, and the regression equation was y = 2.5101x + 42.423. Selenium content of the diet above 0.1 mg x kg(-1) DM seems to supply adequate selenium requirements for dromedaries under intensive husbandry.     

Dual oxidase 2 and glutathione peroxidase gene expression are elevated in hyperimmunized sheep challenged with Haemonchus contortus

A sequential biopsy sampling method was used to investigate oxidant and antioxidant gene responses in resistant sheep challenged with Haemonchus contortus larvae or a sham saline challenge. The expression of key sheep oxidant and antioxidant producing genes were measured in sequential samples removed from the abomasums at days 0, 1, 2, 3, 5, 7 and 28 post challenge. Gene expression levels at each time point were compared to expression at day 0, and levels of the various genes were also correlated to other markers of infection including immune cell counts and cytokine gene expression. The early response to larval challenge infection in resistant animals was marked by a divergence of two groups of host oxidant producing genes: the dual oxidase group (DUOX2/DUOXA2) showing increases in expression to day 7, while members of the phagocytic NADPH oxidase (PHOX) group showed significant decreases in expression. The change in DUOX2 expression between days zero and seven, when host resistance to infection is mediated, was negatively correlated to final worm burden suggesting NADPH oxidase expression may play a role in parasite expulsion. Expression of the DUOX group oxidants was positively correlated to expression of the Th2 cytokine IL4. Changes in host antioxidant pathways between different members of the glutathione peroxidase family (intestinal and plasma GPX) and genes involved in glutathione metabolism were also observed. This first study of the putative roles of oxidant production by the dual oxidase group, antioxidant glutathione pathways, immune cell populations, and cytokine profiles, in the development of resistance to infection by hyperimmune sheep are discussed.     

Tissue distribution of monomeric glutathione peroxidase in broiler chicks.

It is known that there are two kinds of enzymes which show glutathione peroxidase activity, 'classical' glutathione peroxidase and glutathione S-transferase. Recently, a third enzyme was found, monomeric glutathione peroxidase, in broiler chick liver cytosolic fraction. To gain an insight into the possible physiological role of the monomeric glutathione peroxidase, the distribution of this enzyme in other broiler tissues was studied. The monomeric glutathione peroxidase was found in all tissues examined and in erythrocytes. The percentage of the total glutathione peroxidase activity accounted for by the monomeric enzyme ranged from 4 per cent in erythrocytes to 28 per cent in liver. Livers from three avian and two mammalian species contained the monomeric glutathione peroxidase. The contribution of the monomeric enzyme to total glutathione peroxidase activity with cumene hydroperoxide was high in poultry livers, while only trace monomeric glutathione peroxidase activity was found in mammalian livers. Chick monomeric glutathione peroxidase showed high activity toward phospholipid hydroperoxide. Thus, monomeric glutathione peroxidase might be an important enzyme in reducing membrane lipid hydroperoxides in birds.