In vitro effects of nonylphenol on motility,mitochondrial, acrosomal and chromatin integrity of ram and boar spermatozoa

The objective of this study was to determine the effects of nonylphenol (NP) on viability of ram and boar sperm in vitro. Ram or boar spermatozoa were exposed to 1, 10, 100, 250 and 500 μg NP ml^?1 for 1, 2, 3 or 4 h. Computer‐assisted sperm motility analysis (CASA) system was used to evaluate sperm motility characteristics. Flow cytometry was used to determine mitochondrial membrane potential (MMP) and chromatin integrity, while epifluorescent microscopy was used to determine sperm acrosomal status. Exposure of both species spermatozoa to 250 and 500 μg NP ml^?1 was detrimental to progressive motility (P < 0.05), and its adverse effect was significant at lower (100 μg NP ml^?1) concentration (P < 0.05). The percentages of ram and boar spermatozoa with high MMP declined drastically after exposures to ≥250 μg ml^?1 NP (P < 0.05). Unlike chromatin integrity, which did not appear to be altered by NP exposure, there were dose‐dependent NP effects (P < 0.05) on acrosomal integrity of both species at as low as 1 μg ml^?1 NP for boar spermatozoa and 10 μg ml^?1 NP for ram spermatozoa. These data show adverse effects of NP on ram and boar spermatozoa and thus its potential harmful effects on male reproduction as NP is found in fruits, vegetables, human milk, fish and livestock products.     

Estrogenic chemicals at body burden levels attenuate energy metabolism in 3T3‐L1 adipocytes

The study aimed to examine effects of environmental estrogens at body burden levels on energy metabolism in fat cells. Acclimation of T47D‐KBluc cells in estrogen‐deprived medium was established for high performance of estrogen‐responsive luciferase reporter assay. With the assay, relative estrogenic potency of four selected estrogen receptor (ER) agonists, i.e. diethylstilbestrol, β‐estradiol, 4‐nonylphenol and bisphenol A, were determined. Immunoblot analysis revealed that the ER agonists at both EC₈₀ and EC₁₀₀ caused rapid and transient phosphorylation of extracellular signal‐regulated kinases (ERK) in an ER‐dependent manner. 3T3‐L1 adipocytes treated with the ER agonists at EC₈₀ for 24 hours exhibited significant downregulation in mitochondrial respiration and glycolytic function. Importantly, EC₈₀ values of 4‐nonylphenol (6.0 × 10⁻¹⁰ m ) and bisphenol A (1.0 × 10⁻⁸ m ) are in the range of human body burdens. The finding that estrogenic chemicals at body burden levels cause significant impact on fat cell energy metabolism raises an important public health issue that deserves more attention.     

壬基酚对红鲫、草鱼和鲢鱼的毒性及组织蓄积研究

目的了解不同鱼种对壬基酚的毒性差异。方法选择红鲫、草鱼和鲢鱼鱼苗,4-壬基酚换水式染毒进行96h急性毒性试验、12周亚慢性毒性试验、外周血红细胞微核试验,高效液相色谱法测定组织中4-壬基酚。结果①4-壬基酚对红鲫、草鱼和鲢鱼的96h LC50分别为251.30、155.84和187.01μg/L。②染毒12周,红鲫高剂量组肝胰脏系数降低,中、高剂量组卵巢系数增高(P<0.05);草鱼中剂量组肾脏系数降低(P<0.05);鲢鱼高剂量组肝胰脏系数降低(P<0.05)。③染毒4周时,红鲫和鲢鱼中、高剂量组及草鱼高剂量组微核细胞率与对照组相比显著增高(P<0.05);染毒8周及以后,受试鱼各剂量组微核细胞率均增高(P<0.05);④受试鱼肌肉、脑和肝胰脏等组织样品中均有4-壬基酚检出,其中肝胰脏的生物浓缩系数最高;红鲫对4-壬基酚的生物浓缩系数高于草鱼和鲢鱼。结论红鲫对壬基酚较敏感。     

壬基酚和镉离子在体外对小鼠精子顶体反应的影响

目的:研究壬基酚和镉离子在体外对小鼠精子顶体反应(AR)的影响。方法:从小鼠的输精管获得精子,体外培养使精子获能,加30μmol/L的A23187诱导精子顶体反应,然后使用不同浓度的壬基酚(10、20、30、60、100μmol/L),或者镉离子(500、2500、5000μmol/L)处理,对照组使用相应的载体溶剂处理。用FITC-PSA荧光染色法分析精子顶体反应。结果:当壬基酚浓度<30μmol/L时,小鼠精子顶体反应率与对照组比较没有显著差异(P>0.05),而当壬基酚浓度>60μmol/L时能够显著地抑制小鼠精子顶体反应发生率(P<0.01),并且观察到精子存活率随着壬基酚浓度增加而降低。与壬基酚作用不同,用镉离子对小鼠精子进行处理,在所选浓度内(500~5 000μmol/L)均对精子顶体反应无显著影响(P>0.05),且精子存活率与镉离子浓度变化无关。结论:壬基酚与镉离子对小鼠精子发生的作用是通过不同的途径来实现的,前者可以直接抑制顶体反应,而后者则与精子顶体反应无关。     

聚氧乙烯型非离子表面活性剂的电喷雾质谱行为

聚氧乙烯型表面活性剂是一类重要的非离子型表面活性剂，易与阳离子形成加合离子[M＋X]^＋。应用电喷雾飞行时间质谱仪（ESI—TOF—MS），以直接进样的方式，对壬基酚聚氧乙烯醚加合离子进行了研究。通常在谱图中可见钠、钾加合离子[M＋-Na]^＋、[M＋K]^＋。样品中的钠、钾离子的浓度影响对应加合离子的谱峰强度。样品中加入．MgCl2，可在谱图上观察到[M＋MgCl]^＋离子的谱峰。用高分辨电喷雾质谱确定[M＋18]^＋峰对应于[M＋NH4]^＋。     

孕期和哺乳期暴露壬基酚对仔鼠肝脏细胞色素P450 2E1 mRNA及蛋白表达的影响

目的 探讨孕期和哺乳期暴露壬基酚(NP)对仔鼠肝脏细胞色素P450 2E1 (CYP2E1) mRNA和蛋白表达的影响.方法 将孕鼠分为低、中、高剂量染毒组(分别给予50、100、200 mg·kg-1·d-1 NP染毒)和对照组,孕鼠受孕第6天到仔鼠出生21 d灌胃染毒NP.仔鼠出生90 d后处死,检测血清肝功能指标及血脂水平,观察肝脏病理学变化,测定肝组织谷胱甘肽过氧化物酶(GSH-PX)、超氧化物歧化酶(SOD)活性及丙二醛(MDA)水平,检测CYP2E1 mRNA和蛋白表达水平.结果 与时照组比较,各染毒组仔鼠血清丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)水平及AST/ALT比值均升高(P＜0.05),且随染毒剂量的增加呈上升趋势;血清三酰甘油(TG)、总胆固醇(TC)及低密度脂蛋白胆固醇(LDL-C)水平均较对照组升高(P＜0.05).对照组仔鼠肝组织结构正常,低剂量染毒组仔鼠肝脏肝窦轻度扩张,中剂量染毒组仔鼠肝脏有轻度炎性细胞灶性浸润,高剂量染毒组仔鼠肝脏有大量脂滴存在.各染毒组仔鼠肝组织SOD、GSH-PX活性明显低于对照组(P＜0.05),MDA水平明显高于对照组(P＜0.05).中、高剂量染毒组与对照组比较CYP2E1 mRNA和蛋白表达水平均升高(P＜0.05).结论 孕期和哺乳期暴露NP,可致仔鼠肝脏脂质代谢紊乱及炎性损伤,可能与肝脏CYP2E1表达上调有关.     

Effects of nonylphenol on the calcium signal and catecholamine secretion coupled with nicotinic acetylcholine receptors in bovine adrenal chromaffin cells

Nonylphenol (NP) is the most critical metabolite of alkylphenol polyethoxylate detergents. NP is known as an endocrine disruptor with estrogenic activities and as an inhibitor of endoplasmic reticulum Ca(2+)-ATPase. Estrogen has modulatory roles on ligand-gated ion channels, such as nicotinic acetylcholine receptors (nAChRs). Ca(2+)-ATPase inhibitors can modulate the cytosolic calcium concentration ([Ca(2+)](c)]) and thus can affect the calcium signaling coupled with nAChRs. Therefore, NP is predicted to have complex effects on the Ca(2+) signaling and secretion coupled with nAChRs. This study investigated these effects using bovine adrenal chromaffin cells. The results show that NP suppressed the Ca(2+) signaling coupled with nAChRs and voltage-operated Ca(2+) channels in a dose-dependent manner, with IC(50)s of 1 and 5.9 microM, respectively. Estradiol exhibits similar suppression but much lower inhibitory potencies. NP alone induced a transient rise in [Ca(2+)](c) in the presence or absence of extracellular calcium. Thapsigargin, an endoplasmic reticulum Ca(2+)-ATPase inhibitor, partially suppressed the [Ca(2+)](c) rise induced by NP, but NP totally blocked the [Ca(2+)](c) rise induced by thapsigargin. This illustrates that NP can cause Ca(2+) release from thapsigargin-insensitive pools. Thapsigargin suppressed the Ca(2+) signaling coupled with nAChRs but increased that coupled with voltage-operated Ca(2+) channels. We propose that three routes are responsible for the effects of NP on nAChRs: named receptor channels, voltage-gated Ca(2+) channels, and Ca(2+)-induced Ca(2+) release. Three routes are related to the characteristics of NP as steroid-like compounds and Ca(2+)-ATPase inhibitor.     

p-Nonylphenol, 4-tert-octylphenol and bisphenol A increase the expression of progesterone receptor mRNA in the frontal cortex of adult ovariectomized rats

Alkylphenols, such as p-nonylphenol (NP) and 4-tert-octylphenol (OP) and bisphenol A (BPA) are thought to mimic oestrogens in their action, and are called endocrine disrupters. We examined whether these endocrine disrupters affected progesterone receptor (PR) mRNA expression in the adult female rat neocortex. In one experiment, at 12.00 h, ovariectomized rats were given a subcutaneous injection of 10 mg of NP, 10 mg of OP or 10 mg of BPA, or sesame oil alone as control. Twenty-four hours after injection, the left side of the frontal cortex, parietal cortex and temporal cortex was collected. In a second experiment to study the time-course of the effects of BPA on PR mRNA, the ovariectomized rats were given a subcutaneous injection of 10 mg of BPA and killed 0, 6, 12 and 24 h after injection. In addition to the frontal cortex and temporal cortex, the occipital cortex was also collected. Northern blotting revealed that, in the first experiment, injection of NP, OP or BPA significantly increased PR mRNA expression in the frontal cortex but not in the parietal cortex. In the temporal cortex, BPA significantly decreased PR mRNA, but NP and OP produced no significant changes. The second experiment revealed that, in the frontal cortex, BPA induced a significant increase in PR mRNA expression at 6 h after injection, which lasted until 24 h after injection. In the temporal cortex, PR mRNA expression was significantly decreased 6 h after injection of BPA and was still significantly low 24 h after injection. No significant change was observed in the occipital cortex. These results suggest that, even in adult rats, endocrine disrupters alter the neocortical function by affecting the PR system, although the physiological significance of PR in the affected area is unknown.     

壬基酚对卵巢癌细胞和蛋白表达的影响

目的　观察环境雌激素化合物壬基酚 (nonylphenol,NP)对卵巢癌细胞 (PEO4 )c -myc和 p5 3mRNA及蛋白表达的影响 ,以探讨NP雌激素活性的分子生物学作用机制。方法　将PEO4细胞在DMEM培养液中进行常规传代培养。采用MTT比色法观察NP对PEO4细胞增殖的影响 ,用逆转录聚合酶链反应 (RT -PCR)技术和免疫组化方法检测NP对c -myc原癌基因和p5 3抑癌基因表达的影响。 结果　与溶剂对照组相比 ,在 (8～ 96 )× 10 -7mol/L浓度范围内 ,NP与 8× 10 -9mol/L雌二醇作用类似可显著促进PEO4细胞增殖 (P <0 0 5 ) ,并表现出良好的剂量 -效应和时间 -效应关系。RT -PCR及免疫组化结果显示 ,32× 10 -7mol/LNP可促进卵巢癌细胞PEO4c -myc和 p5 3mR NA及蛋白表达。结论　NP具有雌激素样生物活性 ,可促进雌激素反应性肿瘤细胞PEO4增殖 ,这一效应主要是通过影响c-mycmRNA和蛋白质的表达而实现的。     

壬基酚对体外培养大鼠胚胎发育的毒性研究

目的 研究4-壬基酚(4-NP)在体外条件下对大鼠胚胎生长发育的影响，探讨其胚胎毒性作用机制。方法 采用植入后全胚胎培养模型，将9.5d Wistar大鼠胚胎与含4-NP的大鼠即刻离心血清共培养48h(4-NP终浓度为0，6.25，12.5，25，50，100mg/L)，观察4-NP对大鼠胚胎生长发育和组织器官形态分化的影响，并用光镜、电镜检测胚胎和卵黄囊的组织结构。结果 4-NP在25mg/L以上可诱发卵黄囊生长和血管分化不良、胚胎生长迟缓及器官形态分化异常，严重者出现神经系统、心脏、腮弓发育异常及小肢芽、体位异常等畸形；100mg/L的4-NP对体外培养胚胎主要呈致死效应。光镜可见实验组胚胎多个器官组织出现病理改变，光镜和电镜下可见卵黄囊3层结构受损，以上结果均呈明显的剂量-反应关系。结论 4-NP对体外培养的大鼠胚胎具有-定的胚胎毒性。其胚胎毒性机制可能与4-NP对卵黄囊胎盘的结构和功能的破坏及其直接的细胞毒性有关。