The effect of endocrine disruptors on the reproductive system - current knowledge.

OBJECTIVE: Chemicals that disrupt the endocrine homeostasis of the human body, otherwise known as endocrine disruptors (EDCs), are found in the blood, urine, amniotic fluid, or adipose tissue. This paper presents the current knowledge about EDCs and the reproductive system. MATERIALS AND METHODS: The article is an overview of the impact of EDCs and their mechanism of action, with particular emphasis on gonads, based on the information available on medical databases (PubMed, Web of Science, EMBASE and Google Scholar, EMBASE and Web of Science) until May 2021. RESULTS: EDCs occur in everyday life, e.g., they are components of adhesives, brake fluids, and flame retardants; they are used in the production of polyvinyl chloride (PVC), plastic food boxes, pacifiers, medicines, cosmetics (bisphenol A, phthalates), hydraulic fluids, printing inks (polychlorinated biphenyls - PCBs), receipts (bisphenol A, BSA) and raincoats (phthalates); they are also a component of polyvinyl products (e.g. toys) (phthalates), air fresheners and cleaning agents (phthalates); moreover, they can be found in the smoke from burning wood (dioxins), and in soil or plants (pesticides). EDCs are part of our diet and can be found in vegetables, fruits, green tea, chocolate and red wine (phytoestrogens). In addition to infertility, they can lead to premature puberty and even cause uterine and ovarian cancer. However, in men, they reduce testosterone levels, reduce the quality of sperm, and cause benign testicular tumors. CONCLUSIONS: Therefore, this article submits that EDCs negatively affect our health, disrupting the functioning of the endocrine system, and particularly affecting the functioning of the gonads.

Immunomodulation inhibits the development of endometriosis in rats.

Endometriosis, the presence of ectopic endometrium, has an unclear etiology and is commonly associated with endocrine, genetic, and immunological imbalance. This study determined whether immunomodulation by the RESAN vaccine could alter the potentially pathogenic gene expression profiles in the cells of the eutopic endometrium in an animal model of endometriosis. Preventing these changes could inhibit the early development of the illness and support the success of surgical treatment. Wistar rats were divided into three groups: prophylaxis (vaccinated before ectopic endometrium implantation, n = 23), therapeutic (vaccinated at the time of the ectopic excision, n = 23) and control (n = 10). During the first laparotomy, autotransplantation of the endometrium to the peritoneum was performed in the prophylaxis and therapeutic groups. The second laparotomy was carried out three months later in all groups to examine endometriotic foci and adhesions. Suspected endometriosis foci were removed. Three months later, the third laparotomy was performed in all animals, followed by suspected foci excision. Fragments of the eutopic endometrium were collected from all animals during the first and third laparotomies. All samples were analysed by real-time PCR to assess the expression of Bcl2, Bax, Bax/Bcl2 ratio, Mki67, and Tert genes. Endometrial foci were found in abdominal peritoneum at the second laparotomy in 1 animal in the prophylaxis group, compared to 16 animals in the therapeutic group. The prophylaxis group showed a high expression of Bax while the therapeutic group showed high expression of Bax, Tert and Mki67 genes. Additional analysis revealed that throughout the six months of the experiment, the expression of the Bax, Tert, and Mki67 genes decreased significantly in the prophylaxis group, Mki67 gene expression decreased in the therapeutic group, and Tert, Mki67, and Bcl2 gene expression decreased in the control group. The results indicate that immunomodulation affects the balance between apoptosis and proliferation in the eutopic endometrium and may prevent the onset and recurrence of endometriosis.

The effect of tobacco smoke on oxytocin concentrations and selected oxidative stress parameters in plasma during pregnancy and post-partum - an experimental model.

BACKGROUND: Tobacco smoking is a serious threat to life and health of society. Among the most vulnerable to the toxic effects of tobacco smoke are foetuses and newborns. The objective of the research was to assess the impact of tobacco smoke exposure on oxytocin levels and biochemical oxidative stress parameters during pregnancy and after birth in an experimental model. METHODS: In the experiment, exposure to tobacco smoke of gravid and non-gravid rats was monitored. A reliable biomarker of exposure - cotinine - was used in the process and it was determined by means of high-performance liquid chromatography with diode array detection, which ensured high analytical accuracy and precision. Determination of oxytocin was performed by means of enzyme-linked immunosorbent assay. The levels of selected oxidative stress parameters: total protein concentration, uric acid, trolox equivalent antioxidant capacity, protein S-nitrosylation and lipid peroxidation (thiobarbituric acid reactive substances) were measured by spectrophotometric methods. RESULTS AND CONCLUSIONS: The effect of prenatal and postnatal exposure to tobacco smoke was a lower medium body mass of rat foetuses and pups. Oxidative stress during pregnancy, additionally intensified by tobacco smoke exposure, led to adaptive changes in properties of plasmatic antioxidant barriers. Moreover, the disturbance of oxidoreductive balance by tobacco smoke affects oxytocin fluctuations, what was observed in this study during lactation period. Therefore, women who smoke may breastfeed their children less frequently and for a shorter period.

An influence of immunomodulation on Th1 and Th2 immune response in endometriosis in an animal model.

AIM: To assess the role of the Th1 and Th2 cellular response in the etiology of endometriosis observed in a rat model, with the use of the RESAN immunomodulator. MATERIALS AND METHODS: A comparative analysis of cytokines in blood serum typical of Th1 (TNF-α and INF-γ ) and Th2 (IL-4, IL-6, IL-10) cell response in groups of rats, in which RESAN preparation was used as prophylaxis (Gr. I) or treatment (Gr. II) of endometriosis. RESULTS: The results indicated an increase in the level of cytokines in blood serum typical of Th2 cell response by comparing the second and third stages of the experiment in the second group of rats and a decrease in IL-4 and IL-10 between III and IV stages. There was a significant difference in cytokine levels during the third stage of the experiment by comparing I and II groups of rats. In the III group of rats, levels of IL-10 significantly increased between the II and III stages of the experiment. CONCLUSION: RESAN preparation shows Th2 cell response, inhibiting the development of endometriosis in a rat model. Due to successful prophylactic action, one may speculate that RESAN vaccine may be effective as a complementary treatment after surgical excision.

Influence of tobacco smoke on the pharmacokinetics of citalopram and its enantiomers.

The purpose of this study was to evaluate the influence of tobacco smoke on the pharmacokinetics of citalopram (CIT) and desmethylcitalopram (DCIT) and its enantiomers on an animal model. High performance liquid chromatography (HPLC) with a diode array detector (DAD) was used for the identification and quantification of the studied compounds. The HPLC quantification of racemic mixtures of CIT was performed on a C18 column. The limits of detection (LOD) and quantification (LOQ) were: 7 and 10 ng/ml respectively. HPLC separation of citalopram enantiomers (S- and R-CIT) was performed on a Chirobiotic V column. The limits of detection (LOD) and quantification (LOQ) were: 6 and 15 ng/ml for R- and S-CIT respectively. The experiment was carried out on male Wistar rats. The rats were exposed to tobacco smoke for five days (6 hours per day). After the exposure, citalopram was administered in a dose of 10 mg/kg intragastrically. In the control group (non-exposed animals), citalopram was administered in the same way and at an equal dose. The blood of the animals was collected at nine time points. It was found that tobacco smoke exposure inhibits the biotransformation of citalopram. The half-life of the racemic mixture of citalopram after intragastric administration was increased by about 287%. Changes in the pharmacokinetic parameters of S-citalopram (active isomer) show a similar tendency to those of the racemic mixture. The pharmacokinetics of R-citalopram showed no statistically important differences after tobacco smoke exposure. Alterations in the pharmacological parameters of desmethylcitalopram presented an opposite trend to the parent drug. After exposure to tobacco smoke, the induction of metabolism of this compound was observed.

Effect of maternal tobacco smoking or exposure to second-hand smoke on the levels of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) in urine of mother and the first urine of newborn.

Tobacco smoking during pregnancy is associated with a variety of negative consequences not only for the mother, but also for the developing fetus. Many studies have shown that carcinogens contained in tobacco smoke permeate across the placenta, and are found in fetus. The aim of the study was to determine the prenatal exposure to tobacco-specific carcinogenic N-nitrosamines on the basis of measurements of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) in urine of smoking and second-hand smoke (SHS) exposed women and in the first urine of their newborns. A questionnaire documenting demographics and socio-economical data, smoking habits and exposure to SHS was completed by 121 delivering women near or at term. Maternal concentrations of cotinine and NNAL were measured in urine of the mother and the first urine of her newborn infant by liquid chromatography tandem mass spectrometry (LC/MS/MS). The mean concentration of cotinine was 439.2 ng/mg creatinine and NNAL concentration in urine of smoking women was 74.0 pg/mg creatinine, and for her newborn 78.6 pg/mg creatinine. Among mothers exposed to SHS, cotinine and NNAL mean concentration were 23.1 ng/mg creatinine, and 26.4 pg/mg creatinine. In newborns of SHS exposed mothers during pregnancy the mean concentration of NNAL was 34.1 pg/mg creatinine, respectively. Active tobacco smoking as well as passive exposure to smoking during pregnancy is an important source of tobacco specific N-nitrosamines to the fetuses as evidenced by increased concentrations of this carcinogen. Determination of NNAL in maternal urine samples can be a useful biomarker of prenatal exposure of newborn to carcinogenic nitrosamines.

Morphological changes in lungs, placenta, liver and kidneys of pregnant rats exposed to cigarette smoke.

OBJECTIVE: Histopathological examination of changes in foetal and newborn rats, and histopathological and morphometric assessments of changes in lungs, placenta, liver and kidneys of adult rats exposed to cigarette smoke were performed. METHODS: Non-pregnant and pregnant Wistar female rats were exposed to cigarette smoke at a carbon monoxide concentration of 1500 mg/m(3) for 6 h per day, 5 days per week, for 3 weeks. Levels of urine nicotine and cotinine were used as measures of exposure. Paraffin-embedded, haematoxylin and eosin (HE)-stained sections were used for examination. Morphometry of studied organs was performed using a computer image analyser. RESULTS: Applied smoke dose and exposure time produced dramatic histopathological changes in lungs of exposed rats (emphysema, emphysematous, inflammatory, metaplastic changes) and reduction in height of respiratory-bronchiole epithelium, and considerably less-marked morphological changes in hepatic (number of apoptotic hepatocytes) and renal (height of proximal convoluted tubule epithelium) cells as well as in the placenta (for example, size of giant cells in labyrinth, height of epithelium covering yolk sac ). Exposure to cigarette smoke did not result in histopathological changes in lungs and liver of surviving foetuses. The duration of pregnancy was not changed but a tendency for a decrease in the mothers' fertility indices as well as some changes in foetal and newborn parameters was observed. CONCLUSION: Taking into account the morphological changes observed in adult rat tissues and placentae which can result in definite hormonal and trophic effects on the foetus, the possibility of early or late physiological effects in progeny under the influence of cigarette smoke must be taken into consideration.

The influence of simultaneous whole body exposure to cigarette smoke and low-protein diet feeding on fertility, reproduction, and progeny of rats.

The aim of the present study was to evaluate the toxicological influence of different concentrations of tobacco smoke and low-protein diet on fertility, reproduction, and survival of offspring of Wistar female rats. We studied three generations, two litters in each. There were 192 animals in parent generation. Animals were exposed to three different concentrations of tobacco smoke that were reflected by the carbon monoxide (CO) concentration (500, 1000, and 1500 mg CO/m3 air) during 11 weeks (six before and two weeks during mating, and three weeks of pregnancy). Additionally, animals were divided into two subgroups that were fed normal or low-protein diet. In the present study, we concentrated on the indices describing the reproduction ability, fertility, and rearing of pups of mothers exposed to tobacco smoke. The parameters of newborns survival were estimated also. We concluded that neither tobacco smoke exposure nor the low-protein diet changed the duration of pregnancy. The tobacco smoke in all doses and low-protein diet had a negative influence on fertility, reproduction, and survival of newborns from exposed mothers. This influence was mainly attributed to the tobacco smoke exposure. The levels of carboxyhaemoglobin were increasing with increasing tobacco smoke concentration.

Low activity of the ahr gene in the ahr dd C57BL congenic mice does not prevent the depression of birth rates observed as result of cigarette smoke exposure.

The ahr gene product is a ligand-activated transcription factor which regulates the expression of a number of enzymes involved in the metabolism of aryl hydrocarbons and mediates the effects of dioxins on tumour promotion. We have assessed the cigarette smoke induced depression of the reproductive capacities in the ahr dd C57BL congenic mice and its crosses with C57BL ahr bb mice. The in vivo exposure of animals to toxic concentrations of cigarette smoke during the period of pairing and the early pregnancy was shown by us to affect the reproduction. The transmission of the ahr b and ahr d alleles was assessed by genotyping the STR polymorphism at D12Mit2 locus linked with the ahr gene. Following the exposure to cigarette smoke the changes in the reproductive capacity of the studied mice have been assessed in relation to the presence of the ahr d allele by measurements of the changes in the rates of conceptions, abortions, births and the number of newborns per female after pairings differing in ahr gene alleles and in the expected ahr d allele frequencies in the progeny. The results indicates that the low activity ahr d allele may decrease the abortive effects of cigarette smoke exposure, but does not confer resistance to the depression of births rates following this exposure.

Expression of cytochrome CYP2B1/2 in nonpregnant, pregnant and fetal rats exposed to tobacco smoke.

Four-month-old female Wistar rats were exposed for 20 days to tobacco smoke obtained from non-filter cigarettes. During the exposure, concentration of tobacco smoke was monitored indirectly by measuring the CO level (1500 mg/m3 air). The efficacy of exposure was assessed by measuring urine nicotine and cotinine levels. Cigarette smoke did not change total cytochrome P450 and b5 protein levels in any of the organs studied, and most of these organs did not show any changes in the activity of reductases associated with these cytochromes. Following exposure to tobacco smoke, fetal rat liver expressed CYP2B1/2 protein; in newborns (day 1) both liver and lung showed CYP2B1/2 protein expression and very low pentoxyresorufin O-dealkylase activity. Western blot analysis of adult liver, lung, heart, but not of brain microsomes, showed that tobacco smoke induced CYP2B1/2 in both nonpregnant and pregnant rats, though its expression was lower in the livers and hearts of pregnant females. In the rat and human placenta, neither rat CYP2B1/2 nor human CYP2B6 showed basal or tobacco smoke-induced expression at the protein level. This study shows clearly that the expression of CYP2B1/2, which metabolizes nicotine and some drugs and activates carcinogens, is controlled in rats by age-, pregnancy-, and tissue-specific regulatory mechanisms.

The experimental investigations of the toxic influence of tobacco smoke affecting progeny during pregnancy.

1. Tobacco smoke contains around 4000 substances, most of which are described as toxic, and they may have an influence on the development of progeny. 2. The present studies concentrate on the measurement and calculation of indices describing the new-born's survival, rearing of pups, weight of foetuses, young animals, placenta and females in relation to different doses of tobacco smoke (carbon monoxide levels). The morphological studies of placenta, foetal and newborn lungs were done as a supplement. Biochemical placenta study was also done. 3. The results of the experiment proved that some indices for animals in groups which were passively exposed to the highest concentrations of tobacco smoke were lower, others fluctuated (4 day, 12 day and total survival) and some did not reveal any changes (rearing). Direct correlation between maternal passive exposure to tobacco smoke and the presence of acute respiratory distress syndrome symptoms in new-borns was observed. A decrease of body weight of pregnant females passively exposed to tobacco smoke was also observed. An increase of placenta-foetal factor was found. A decrease of rat weight was observed after passive exposure to tobacco smoke. 4. We concluded that there is correlation between passive exposition to tobacco smoke during pregnancy and delayed lung maturation in the offspring. Exposure of the pregnant rats to cigarette smoke increases the activity of isocitric and glucose-6-phosphate dehydrogenases in placenta.

Passive smoking and pregnancy outcome in central Poland.

1. The present investigation was undertaken to evaluate the effect of environmental tobacco smoke (ETS) on the risk of preterm delivery (PD) and small-for-gestational age (SGA) infants in a female non-smoking population of central Poland. 2. The study group were 1751 women classified as non-smokers in the comprehensive project on 'Socio-economic and environmental risk factors of preterm delivery and small-for-gestationaI-age babies in central Poland' conducted on a randomly selected population of 2080 women who gave birth to a child between June 1, 1996 and May 31, 1997. The PD group comprised 95 non-smoking women who delivered before 37 weeks of pregnancy and the SGA group included 111 non-smoking mothers of babies with birthweight below the 10th percentile of the standard curves for central Poland. Passive exposure to tobacco smoke was determined based on a structured interview. 3. In the stepwise multiple logistic regression model maternal passive smoke exposure lasting 7 h or more was found to be a significant risk factor for preterm delivery. No significant effect of passive smoking on the risk of SGA was observed. 4. The information about the adverse effects of ETS exposure on pregnancy duration and outcome should be incorporated in the health promotion programmes for women.

An experimental study of the influences of tobacco smoke on fertility and reproduction.

1. The aim of this study was to evaluate the toxicological influence of tobacco smoke on fertility and reproduction of Wistar female rats. The influence of tobacco smoke from the Polish 'Popularne' cigarette brand was studied. The experiment was conducted on three generations of animals, each generation having two litters. The initial number of animals of the parent generation F0 was 192 (128 females and 64 males). Animals were passively exposed to tobacco smoke in three different concentrations based on the content of carbon monoxide (500, 1000 and 1500 mg of CO per cubic meter of air). Animals were exposed to tobacco smoke for 6 h a day, 5 days a week, during 11 weeks. 2. The analysis of indices of mating and fertility revealed the decrease in those indices with animals exposed to tobacco smoke. We also observed an increased number of mothers breading among animals exposed to tobacco smoke. In animals exposed to tobacco smoke, the dose-effect or dose-response dependencies for mating, fertility and delivery indices were found. There was no influence of tobacco smoke on the duration of pregnancy. 3. Tobacco smoke inhalation caused increased levels of carboxyhaemoglobin. 4. Tobacco smoke did not change the duration of pregnancy in rats.

Retardation of lung development after maternal cigarette smoking and low protein diet in animal model.

This study has been aimed at showing the influence of tobacco smoke, together with low protein diet on the lungs of newborn rats. The studied animals were Wistar rats. They were exposed to the tobacco smoke for 11 weeks (6 weeks before mating, 12 days during mating, and 21 days of pregnancy). Morphological analysis and interpretation of 48 one-day old rats was based on observation under the light and electron microscope. The study showed atelectasis of the lungs: the lung tissue was insufficiently extended, the alveoli were geometrically irregular and the alveolar septa were thick. Many extravasated erythrocytes and edema (latent as well as overt) were also present. The II type pneumocytes and their surfactant were poorly developed. Tobacco smoke caused the serious pathological effects and together with poor protein diet all changes worsened. For comparison, the lungs of control group were studied (lack of exposure to tobacco smoke); they were well aerated and their structure well-developed.

[The effect of selected xenobiotics and low protein diet on reproduction and offspring of rats. Part I. The course and condition of rat exposure to tobacco smoke]. / Wplyw wybranych ksenobiotyków i diety niskobialkowej na zdolnosc rozrodcza i potomstwo szczurów. CZ. I. Przebieg i warunki ekspozycji zwierzat na dzialanie dymu tytoniowego.

The effect of tobacco smoke and low-protein diet on rat reproducibility and offspring was investigated in six litters of white rats. Smoke concentration was controlled by determining the air carbon oxide content which averaged 1000 mg/m3. During the experiments blood carboxyhemoglobin level was measured; by the end of exposure, each generation displayed closely similar concentrations amounting to 23.9-26.6%. There were no diet-related differences in blood carboxyhemoglobin concentrations.

[Carcinoma metastasis into the vermiform appendix]. / Metastáza karcinomu do appendix vermiformis.

Metastases into the appendix vermiformis are very rare. The authors present a case of a secondary of gastric carcinoma into the appendix vermiformis. In the patient the malignant disease was manifested with the clinical picture of diffuse peritonitis caused by perforation of the aboral portion of the appendix vermiformis at the site of the exulcerated secondary of the carcinoma. The authors give also an account of secondaries into the appendix vermiformis described in the literature.