Investigation of the potential effects of triclosan as an endocrine disruptor in female rats: Uterotrophic assay and two-generation study

Potential oestrogenic effects (following the OECD test guideline 440) and thyroid dysfunction induced by pure cyanotoxins (microcystin-LR, cylindrospermopsin) in rats

Potential endocrine-disrupting properties of cyanotoxins, such as microcystin-LR (MC-LR) and cylindrospermopsin (CYN) are of concern due to their increasing occurrence, the scarcity of reports on the topic (particularly for CYN) and the impact of human's health at different levels. Thus, this work performed for the first time the uterotrophic bioassay in rats, following the Organization for Economic Cooperation and Development (OECD) Test Guideline 440, to explore the oestrogenic properties of CYN and MC-LR (75, 150, 300 μg/kg b.w./day) in ovariectomized (OVX) rats. Results revealed neither changes in the wet and blotted uterus weights nor in the morphometric study of uteri. Moreover, among the steroid hormones analysed in serum, the most remarkable effect was the dose-dependent increase in progesterone (P) levels in rats exposed to MC-LR. Additionally, a histopathology study of thyroids and serum levels of thyroids hormones were determined. Tissue affectation (follicular hypertrophy, exfoliated epithelium, hyperplasia) was observed, as well as increased T3 and T4 levels in rats exposed to both toxins. Taken together, these results point out that CYN and MC-LR are not oestrogenic compounds at the conditions tested in the uterotrophic assay in OVX rats, but, however, thyroid disruption effects cannot be discarded.

Effect of triclosan exposure on ovarian hormones, trace elements and growth in female rats

Triclosan (TCS) is an antibacterial compound used mainly in personal care products. Its widespread use for decades has made it one of the most widely detected compounds in environmental matrices and in biological fluids. Although it has been shown to be an endocrine disruptor in rats and aquatic species, its safe use by humans is unclear. The aim of the present study was to evaluate the effects of exposure to TCS in female rats. To this end, 14 rats were divided into two groups and fed daily as follows: the control group with sesame oil and the TCS group at a dose of 50 mg/kg/day for 28 days. Any signs of toxicity in the rats were observed daily, and the weight and phase of the estrous cycle were recorded. At the end, the rats were decapitated, the serum and ovaries were collected. The levels of testosterone and progesterone in serum were determined by immunoassay and mass spectrometry. Estradiol (in serum) and kisspeptin-10 (in serum and ovary) were measured only by immunoassays. Trace elements were determined by inductively coupled plasma-mass spectrometry (ICP-MS). The weight gain study of the rats showed a significant decrease by exposure to TCS, while the estrous cycle was not significantly affected compared to the control. The optimized methods based on mass spectrometry showed a significant decrease in the levels of progesterone and testosterone due to exposure to TCS. In addition, elements determined by ICP-MS in rat serum showed significant changes in calcium, lithium and aluminum due to TCS treatment. Finally, the kisspeptin-10 levels did not show a negative effect due to the treatment by TCS. The results suggest that medium-term exposure to TCS did not significantly alter estrous cyclicity but caused alterations in growth, sex hormone levels and some elements in the rat serum.

Implications of triclosan for female fertility: results from the National Health and Nutrition Examination Survey, 2013-2016

Objective

To examine and further characterize the association between urinary levels of triclosan (TCS), a ubiquitous putative endocrine-disrupting chemical, and the risk of infertility.

Design

A retrospective cross-sectional study using the Centers for Disease Control and Prevention's National Health and Nutrition Examination Survey.

Setting

Not applicable.

Patients

Female participants in the United States who completed the reproductive health questionnaire and provided urine samples for TCS level measurement from 2013 to 2016.

Interventions

None.

Main Outcome Measures

Rates of presumed infertility based on participants' affirmative response to survey question RHQ074 ("Have you ever attempted to become pregnant over a period of at least a year without becoming pregnant?").

Results

A total of 11.7% of the overall female and 12.5% of the eligible study population met the criterion for presumed infertility. Creatinine-adjusted urinary TCS levels were significantly higher among those meeting the criterion for infertility compared with the levels among those who did not. On multivariable-adjusted analyses, individuals with undetectable levels of urinary TCS were 35% less likely to meet the specified infertility criterion compared with those with detectable TCS levels. The magnitude of association between TCS levels and infertility was strongest when comparing the lowest and highest quartiles. The directionality and magnitude of the relationship between TCS levels and infertility were maintained on age-restricted and weighted analyses; however, the associations did not retain statistical significance.

Conclusions

In a nationally representative sample of women in the United States, an association between TCS exposure and inability to conceive over a period of 1 year is suggested by our analysis of the National Health and Nutrition Examination Survey data. The data infer a dose-response relationship.

Pharmaceutical and personal care products as emerging environmental contaminants in Nigeria: A systematic review

The increasingly broad and massive use of pharmaceuticals (human, veterinary) and personal care products in industrially developing nations makes their uncontrolled environmental and ecological impact a true concern. Focusing on Nigeria, this systematic literature search (databases: PubMed, ScienceDirect, Google Scholar, EMBASE, Scopus, Cochrane library and African Journals Online) aims to increase visibility to the issue. Among 275 articles identified, 7 were included in this systematic review. Studies indicated the presence of 11 personal care products (15.94 %) and 58 pharmaceutical products (84.06 %) in surface and ground water, leachates, runoffs, sludge, and sediments. The 42.86% (3/7) of reviewed studies reported 17 analgesics; 71.42 % (5/7) reported 16 antibiotics; 28.57 % (2/7) reported 5 lipid lowering drugs; 28.57% reported anti-malaria and fungal drugs; 14.29 % (1/7) reported estrogen drugs. Different studies report on sunscreen products, hormone, phytosterol, insect repellent, and β1 receptor. Gemfibrozil (<4-730 ng/L), Triclosan (55.1-297.7 ng/L), Triclocarban (35.6-232.4 ng/L), Trimethoprim (<1-388 ng/L) and Tramadol (<2-883 ng/L) had the highest range of concentrations. Findings confirm the need of i) legislation for environmental monitoring, including biota, ii) toxicological profiling of new market products, and iii) sensitization on appropriate use and disposal of pharmaceuticals and personal care products.

Monitoring of Pollutants Content in Bottled and Tap Drinking Water in Italy

The concentration levels of thirteen organic pollutants and selected heavy metals were investigated in 40 plastics bottled and tap water samples. Some of the selected contaminants have an ascertained or suspected endocrine disrupting activity, such as Bisphenol A (BPA) and its analogs, and Bis 2-ethylhexyl phthalate (DEHP), which are used by industries as plasticizers. The most frequently detected pollutants were Bisphenol AF (BPAF) (detection frequency (DF) = 67.5%, mean 387.21 ng L⁻¹), DEHP (DF = 62.5%, mean 46.19 µg L⁻¹) and BPA (DF = 60.0%, mean 458.57 ng L⁻¹), with higher concentration levels found in tap waters. Furthermore, a possible level of exposure to thirteen pollutants via drinking water intake was calculated. Our findings show that, even though the occurrence of contaminants and heavy metals in drinking waters does not pose an immediate, acute health risk for the population, their levels should be constantly monitored and “hard-wired” into everyday practice. Indeed, the health impact to the continuous and simultaneous intake of a huge variety of xenobiotics from various sources by humans is complex and still not fully understood.

Baseline and time-updated factors in preclinical development of anionic dendrimers as successful anti-HIV-1 vaginal microbicides

Although a wide variety of topical microbicides provide promising in vitro and in vivo efficacy, most of them failed to prevent sexual transmission of human immunodeficiency virus type 1 (HIV‐1) in human clinical trials. In vitro, ex vivo, and in vivo models must be optimized, considering the knowledge acquired from unsuccessful and successful clinical trials to improve the current gaps and the preclinical development protocols. To date, dendrimers are the only nanotool that has advanced to human clinical trials as topical microbicides to prevent HIV‐1 transmission. This fact demonstrates the importance and the potential of these molecules as microbicides. Polyanionic dendrimers are highly branched nanocompounds with potent activity against HIV‐1 that disturb HIV‐1 entry. Herein, the most significant advancements in topical microbicide development, trying to mimic the real‐life conditions as closely as possible, are discussed. This review also provides the preclinical assays that anionic dendrimers have passed as microbicides because they can improve current antiviral treatments' efficacy.

This article is categorized under:

Nanotechnology Approaches to Biology > Nanoscale Systems in Biology

Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease

Toxicology and Regulatory Issues in Nanomedicine > Regulatory and Policy Issues in Nanomedicine

Sulfasalazine exposure during pregnancy and lactation induces alterations in reproductive behavior in adult female rat offspring

AIMS

Sulfasalazine (SAS) is the first line drug in the treatment of chronic inflammatory bowel diseases in pregnant women. SAS and its metabolites cross the placenta and can be transferred through the milk. However, the long-term consequences to the reproductive system of offspring from dams exposed to SAS have not yet been studied. Thus, our study investigated the effects of SAS treatment during gestational and lactational periods on maternal care in F0 and reproductive outcomes in F1 females.

MAIN METHODS

Wistar female rats (n = 10/group) received 300 mg/kg/day of SAS dissolved in carboxymethyl cellulose (CMC), by gavage, from gestational day 0 to lactation day 21 and 3 mg/kg/day of folic acid during gestation. The control group received CMC only. On PND 21, the female pups were selected for reproductive evaluation at different time points: infancy and adulthood. The reproductive parameters evaluated were installation of puberty (vaginal opening and first estrus), estrous cyclicity, reproductive organs weight, histological analysis of the ovary follicles and uterus, analysis of oxidative stress in ovarian tissue, reproductive behavior (sexual and maternal), and fertility.

KEY FINDINGS

SAS treatment decreased the retrieving behavior in F0 females. The F1 females presented an increase in the lordosis score, frequency of lordosis of magnitude 3, and lipid peroxidation of ovarian tissues in both infancy and adult life.

SIGNIFICANCE

The SAS effects observed in the current study represent a relevant concern for public health, as they demonstrated that treatment with SAS compromised the maternal motivation of dams and induced reproductive alterations in F1 females.

Developmental and Reproductive Outcomes in Male Rats Exposed to Triclosan: Two-Generation Study

Triclosan (TCS) is a phenolic compound with broad-spectrum antimicrobial action that has been incorporated into a variety of personal care products and other industry segments such as toys, textiles, and plastics. Due to its widespread use, TCS and its derivatives have been detected in several environmental compartments, with potential bioaccumulation and persistence. Indeed, some studies have demonstrated that TCS may act as a potential endocrine disruptor for the reproductive system. In the current study, we are reporting on the results obtained for male rats after a two-generation reproduction toxicity study conducted with TCS. Female and male Wistar rats were treated daily by gavage with TCS at doses of 0.8, 2.4, and 8.0 mg/kg/day or corn oil (control group) over 10 weeks (F0) and over 14 weeks (F1) before mating and then throughout mating, until weaning F2 generations, respectively. TCS exposure decreased sperm viability and motility of F1 rats at the dose of 2.4 mg/kg. The effects of TCS on sperm quality may be related to the exposure window, which includes the programming of reproductive cells that occurs during fetal/neonatal development.

Triclosan: antimicrobial mechanisms, antibiotics interactions, clinical applications, and human health

The large-scale applications of Triclosan in industrial and household products have created many health and environmental concerns. Despite the fears of its drug-resistance and other issues, Triclosan is still an effective drug against many infectious organisms. Knowing the cross-interactions of Triclosan with different antibiotics, bacteria, and humans can provide much-needed information for the risk assessment of this drug. We review the current understanding of the antimicrobial mechanisms of Triclosan, how microbes become resistant to Triclosan, and the synergistic and antagonistic effects of Triclosan with different antibiotics. Current literature on the clinical applications of Triclosan and its effect on fetus/child development are also summarized.

Effect of paracetamol treatment on maternal care and reproductive outcomes in female rat offspring

Paracetamol (PAR) is one of the most commonly used drugs by pregnant women because it is considered safe for the mother and fetus. However, PAR is transferred into breast milk and crosses the blood-placental barrier, being present in the progeny during important stages of development. Intrauterine exposure to PAR may decrease the anogenital distance and follicle reserve in female rodent offspring. Therefore, the aim of the present study was to evaluate whether maternal PAR treatment altered the reproductive behaviour of dams and the sexual development of female rat offspring. Pregnant Wistar rats were gavaged daily with 350mg kg-1 day-1 PAR or water during gestation (from Gestation Day (GD) 6 until delivery) or during gestation and lactation (from GD6 until weaning). Maternal PAR treatment had maternal effects (increased grooming behaviour), and resulted in impaired sexual behaviour, decreased follicle reserve and increased plasma oestradiol concentrations in female offspring.

In utero and lactational exposure to triclocarban: reproductive effects on female rat offspring

Triclocarban (TCC) is an antimicrobial compound widely used in personal care products such as soaps, toothpaste, and shampoo. This agent is incompletely removed by wastewater treatment and represents an environmental contaminant. Recent studies have shown that TCC is associated with some endocrine disruptions. The aim of the present study was to evaluate if TCC exposure during critical periods of development (gestation and lactation) could lead to adverse effects on reproductive and behavior parameters of female offspring. Pregnant female Wistar rats were divided into four groups (n = 8-11/group): Control; TCC 0.3 mg/kg (TCC 0.3); TCC 1.5 mg/kg; TCC 3.0 mg/kg (TCC 3.0); and treated daily by oral gavage from gestational day 0 to lactational day 21. The female pups (F1 generation) were weaned on post-natal day 21 and included in the study. No litter-mates were used for the same group. There was a decrease in estradiol levels in the TCC 0.3 and TCC 3.0 groups. Moreover, there was a decrease in progesterone levels and an increase in pre-implantation loss in the TCC 3.0 group in adulthood. It is suggested, in this study, that the decrease in progesterone biosynthesis could interfere with implantation process. The exposure window to TCC is an important factor, as we found alterations only in the offspring.

A Convenient Plant-Based Detection System to Monitor Androgenic Compound in the Environment

Environmental androgen analogues act as endocrine disruptors, which inhibit the normal function of androgen in animals. In the present work, through the expression of a chimeric gene specified for the production of the anthocyanin in response to androgen DHT (dihydrotestosterone), we generated an indicator Arabidopsis that displays a red color in leaves in the presence of androgen compounds. This construct consists of a ligand-binding domain of the human androgen receptor gene and the poplar transcription factor gene PtrMYB119, which is involved in anthocyanin biosynthesis in poplar and Arabidopsis. The transgenic Arabidopsis XVA-PtrMYB119 displayed a red color in leaves in response to 10 ppm DHT, whereas it did not react in the presence of other androgenic compounds. The transcript level of PtrMYB119 peaked at day 13 of DHT exposure on agar media and then declined to its normal level at day 15. Expressions of anthocyanin biosynthesis genes including chalcone flavanone isomerase, chalcone synthase, flavanone 3-hydroxylase, dihydroflavonol 4-reductase, UFGT (UGT78D2), and anthocyanidin synthase were similar to that of PtrMYB119. It is assumed that this transgenic plant can be used by nonscientists for the detection of androgen DHT in the environment and samples such as food solution without any experimental procedures.