Potential hazards to embryo implantation: A human endometrial in vitro model to identify unwanted antigestagenic actions of chemicals

Embryo implantation is a crucial step in human reproduction and depends on the timely development of a receptive endometrium. The human endometrium is unique among adult tissues due to its dynamic alterations during each menstrual cycle. It hosts the implantation process which is governed by progesterone, whereas 17β-estradiol regulates the preceding proliferation of the endometrium. The receptors for both steroids are targets for drugs and endocrine disrupting chemicals. Chemicals with unwanted antigestagenic actions are potentially hazardous to embryo implantation since many pharmaceutical antiprogestins adversely affect endometrial receptivity. This risk can be addressed by human tissue-specific in vitro assays. As working basis we compiled data on chemicals interacting with the PR. In our experimental work, we developed a flexible in vitro model based on human endometrial Ishikawa cells. Effects of antiprogestin compounds on pre-selected target genes were characterized by sigmoidal concentration-response curves obtained by RT-qPCR. The estrogen sulfotransferase (SULT1E1) was identified as the most responsive target gene by microarray analysis. The agonistic effect of progesterone on SULT1E1 mRNA was concentration-dependently antagonized by RU486 (mifepristone) and ZK137316 and, with lower potency, by 4-nonylphenol, bisphenol A and apigenin. The negative control methyl acetoacetate showed no effect. The effects of progesterone and RU486 were confirmed on the protein level by Western blotting. We demonstrated proof of principle that our Ishikawa model is suitable to study quantitatively effects of antiprogestin-like chemicals on endometrial target genes in comparison to pharmaceutical reference compounds. This test is useful for hazard identification and may contribute to reduce animal studies.     

Chronic blockade of glucocorticoid receptors by RU486 enhances lipopolysaccharide-induced depressive-like behaviour and cytokine production in rats

Although accumulating evidence supports a role for cytokines in the pathophysiology of depression, the cytokine hypothesis of depression is debatable. It has been suggested that neuroendocrine and immune systems acting in concert may have roles in the development and the maintenance of the disease. Glucocorticoid receptor (GR) is the key element which exerts both anti-inflammatory and cytokine-inhibiting effects. Whether functional changes of GR are involved in the pathophysiology of cytokine-induced depression remains elusive. In the present study, the effects of both acute and chronic GR blockade on depressive-like behaviour and cytokine production induced by lipopolysaccharides (LPS), cytokine inducer, were investigated in rats. Acute or chronic blockade of GR was achieved by a single administration or repeated administrations, respectively, of the GR antagonist RU486 (RU). Behavioural measurements, including saccharin preference, locomotor activity, and immobility time, were assessed. The serum levels of proinflammatory cytokines (TNFα, IL-1β, and IFNγ) were determined by ELISA. The results showed that LPS induced significant but transient depressive-like behaviour. Repeated, but not single, administration of RU significantly enhanced and prolonged LPS-induced depressive-like behaviour and an increase in the serum production of TNFα and IFNγ. These results indicate that the effective blockade of GR enhanced the depressive-like behaviour induced by cytokines. Findings from this study suggest that GR dysfunction may be an important contributing factor to the development of cytokine-related depression. These findings add to the growing evidence of mechanisms by which cytokines influence depression.     

Tamoxifen and mifepriston modulate nicotine induced conditioned place preference in female rats

An increasing number of studies suggest that nicotine/tobacco addiction is modulated by ovarian hormones. The levels of estrogen and progesterone appear to be important in the success of quit attempts and smoking cessation. In women smokers with the diagnosis or risk of breast cancer, the estrogen receptor modulator tamoxifen (TAM) is widely used, and even though the detrimental health effects of smoking are known, this vulnerable group has difficulty quitting and continues to smoke. The current study tested the effect of the estrogen receptor modulator TAM and the progesterone receptor antagonist mifepriston (RU486) on nicotine-induced conditioned place preference (CPP) in adult female rats. A three chambered CPP apparatus was used and nicotine was paired with the initially non-preferred chamber. Rats received nicotine or saline and hormone receptor modulators (vehicle, TAM, RU486) in a 2 × 3 experimental design. We have previously shown that nicotine induces CPP in male Sprague-Dawley rats but not in females. Our results show that while nicotine alone does not induce CPP in female rats, rats treated with TAM exhibit nicotine-induced CPP. Although RU486 has an aversive effect when applied alone, this is ameliorated by nicotine. These results confirm the role of ovarian hormone receptors in nicotine-induced CPP and may have clinical implications for developing more efficient smoking cessation approaches in women smokers.     

Brief treatment with the glucocorticoid receptor antagonist mifepristone normalises the corticosterone-induced reduction of adult hippocampal neurogenesis

The glucocorticoid receptor antagonist mifepristone has been shown to rapidly and effectively ameliorate symptoms of psychotic major depression. To better understand its mechanism, we investigated mifepristone's cellular effects, and found that it rapidly reversed a chronic corticosterone-induced reduction of adult neurogenesis in rats. Unlike other antidepressants, mifepristone is particularly potent in a high corticosterone environment. These data indicate that similarly to its clinical efficacy, mifepristone's effects on adult neurogenesis are rapid and positive, and may therefore be important for its mechanism of action.     

RU486调控的红色荧光蛋白真核载体的构建及表达

目的 构建一种带有DsRed红色荧光蛋白报告基因并可经RU486诱导的真核表达载体,并在体外验证其调控表达作用.方法 利用分子生物学技术,将DsRed基因和启动子,以及RU486系统构建成真核可凋控载体pRSl7.RUDsRed.在转染MFC细胞后,运用荧光显微镜和流式细胞技术检测该载体的调控表达.结果 PCR和限制性酶切及测序均证实了载体的正确性.没有RU486时,几乎没有红色荧光蛋白的表达,加入诱导剂RU486后,可以实现红色荧光蛋白的高效表达.结论 成功构建了带有红色荧光蛋白报告基因并可经RU486诱导的真核表达载体,实现了对目的 基凶表达的有效调控,为进一步的基因调控研究和和基因治疗奠定了基础.     

RU486对子宫内膜增生症腺上皮中NF-κB/p65、p16和ki67蛋白表达水平的影响

目的:探讨NF-κB/p65、p16、ki67在RU486治疗子宫内膜增生症前后腺上皮中表达变化的意义。方法:37例因阴道不规则出血刮宫诊断为子宫内膜增生症的患者,按10 mg/d剂量连续服用3个月的RU486进行治疗。采用SP非生物素二步法的免疫组织化学染色法检测治疗前后子宫内膜腺上皮NF-κB/p65、p16、ki67蛋白的表达情况。结果:治疗后NF-κB/p65蛋白的阳性信号强于治疗前(P<0.05),而治疗前后p16蛋白的阳性信号无明显差异(P>0.05),但极强阳性大腺体的数量明显多于其它大腺体(P<0.01);治疗后与治疗前相比ki67蛋白表达量明显下降(P<0.05)。结论:RU486治疗子宫内膜增生症可能与NF-κB/p65介导的信号通路有关;RU486可通过非p16相关的机制降低子宫内膜细胞的增殖活性。     

汝安膜质量标准的研究

目的对汝安膜的质量标准进行研究。方法采用薄层色谱法(TLC)对汝安膜中的主要药材大黄、黄连、黄柏等进行定性鉴别;采用高效液相色谱法测定大黄的有效成分大黄素、大黄酚的含量。结果薄层色谱斑点清晰,分离度好,专属性强。在含量测定中,所建方法能同时测定汝安膜中大黄素、大黄酚2种有效成分。平均回收率为大黄素97.78%(RSD=1.58%),大黄酚98.68%(RSD=1.26%)。结论该实验操作简便,重现性好,结果准确,可作为汝安膜的质量控制标准。