Sex differences in effects on sexual development in rat offspring after pre- and postnatal exposure to triphenyltin chloride

Transcriptomics-based analysis reveals the nephrotoxic effects of triphenyltin (TPT) on SD rats by affecting RAS, AQPs and lipid metabolism

Triphenyltin (TPT) is a class of organotin compounds that are extensively used in industry and agriculture. They have endocrine-disrupting effects and cause severe environmental contamination. Pollutants may accumulate in the kidneys and cause pathological complications. However, the mechanism of TPT's toxicological effects on the kidney remains unclear. This study aimed to investigate the toxic effects and mechanism of action of TPT exposure on renal impairment in rats. Male SD rats were divided into four groups: the Ctrl group (control group), TPT-L group (0.5 mg/kg/d), TPT-M group (1 mg/kg/d), and TPT-H group (2 mg/kg/d). After 28 days of exposure to TPT, we observed the morphology and structure of kidney tissue using HE, PASM, and Masson staining. We also detected serum biochemical indexes, performed transcriptome sequencing of rat kidney tissue using RNA-seq. Furthermore, protein expression levels were measured through immunohistochemistry and gene expression levels were determined using RT-qPCR. The study results indicated a decrease in kidney weight and relative kidney weight after 28 days of exposure to TPT. Additionally, TPT caused damage to kidney structure and function, as evidenced by HE staining, PASM staining, and serum biochemical tests. Transcriptomics identified 352 DEGs, and enrichment analyses revealed that TPT exposure primarily impacted the renin-angiotensin system (RAS). The expression levels of water channel proteins were reduced, and the expression levels of RAS and lipid metabolism-related genes (Mme, Ace, Fasn, Cyp4a8, Cpt1b and Ppard) were significantly decreased in the TPT-treated group. In summary, exposure to TPT may impair renal structure and function in rats by affecting RAS, AQPs, and lipid metabolism.

TMT-based quantitative proteomics analysis of Sprague-Dawley rats liver reveals Triphenyltin induced liver damage and lipid metabolism disorders

Triphenyltin (TPT) is a widely used pesticide that has a negative impact on biological health and production efficiency. In addition, TPT poses a threat to human health through the food chain and environmental pollution. However, the exact mechanism of TPT toxicity remains unclear. In this study, we investigated the hepatotoxicity of TPT and its effects on lipid metabolism using male SD rats as an animal model. Our results from HE and serum biochemical analysis suggested that TPT could damage liver structure and function, resulting in disruption of lipid metabolism. We therefore proceeded to analyze the proteomic response of rat liver tissue after 28 days of treatment with 2 mg/kg/d TPT. Our study demonstrates that TPT has a variety of effects on liver protein expression in rats. Through bioinformatic analysis, we observed significant changes in proteins related to fatty acid oxidation and synthesis due to TPT exposure. Furthermore, western blot and RT-qPCR experiments confirmed that TPT can affect lipid metabolism through the PPAR pathway. These findings suggest that TPT exposure can lead to liver damage, lipid accumulation and metabolic disorders.

Triphenyltin (TPT) exposure causes SD rat liver injury via lipid metabolism disorder and ER stress revealed by transcriptome analysis

BACKGROUND

TPT is an environmental endocrine disruptor that can interfere with endocrine function. However, whether TPT can cause damage to liver structure and function and abnormal lipid metabolism and whether it can cause ER stress is still unclear.

OBJECTIVE

To explore the effect of TPT on liver structure, function and lipid metabolism and whether ER stress occurs.

METHODS

Male SD rats were divided into 4 groups: control group (Ctrl group, TPT-L group (0.5mg/kg/d), TPT-M group (1mg/kg/d), and TPT-H group (2mg/kg/d). After 10 days of continuous gavage, HE staining was used to observe the morphological structure of liver tissue, serum biochemical indicators were detected, gene expression and functional enrichment analysis were performed by RNA-seq, Western Blot was used to detect the protein expression level of liver tissue, and qRT-PCR was used to detect the gene expression.

RESULTS

After TPT exposure, the liver structure damaged; serum TBIL, AST and m-AST levels were significantly increased in the TPT-M group, and serum TG levels were significantly decreased in the TPT-H group. TCHO and TG in liver tissues were significantly increased; transcriptomic analysis detected 105 differential genes. Enrichment analysis showed that TPT exposure mainly affected fatty acid metabolism and drug metabolism in liver tissue, and also affected the redox process of liver tissue; the protein expression levels of PPARα, PPARγ, AMPK, RXRα, IRE1α and PERK were significantly increased after TPT exposure; the expression levels of lipid metabolism-related genes Acsl1, Elovl5, Hmgcr, Hmgcs1 and Srebf1 were significantly increased in the TPT-L group, while in the TPT-M and TPT-H groups had no significant change.

CONCLUSIONS

TPT exposure can cause liver injury, lipid metabolism disorder and ER stress.

Review on endocrine disrupting toxicity of triphenyltin from the perspective of species evolution: Aquatic, amphibious and mammalian

Triphenyltin (TPT) is widely used as a plastic stabilizer, insecticide and the most common fungicide in antifouling coatings. This paper reviewed the main literature evidences on the morphological and physiological changes of animal endocrine system induced by TPT, with emphasis on the research progress of TPT metabolism, neurological and reproductive regulation in animal endocrine system. Similar to tributyltin (TBT), the main effects of TPT on the potential health risks of 25 species of animals, from aquatic animals to mammals, are not only related to exposure dose and time, but also to age, sex and exposed tissue/cells. Moreover, current studies have shown that TPT can directly damage the endocrine glands, interfere with the regulation of neurohormones on endocrine function, and change hormone synthesis and/or the bioavailability (i.e., in the retinoid X receptor and peroxisome proliferator-activated receptor gamma RXR-PPARγ) in target cells. Importantly, TPT can cause biochemical and morphological changes of gonads and abnormal production of steroids, both of which are related to reproductive dysfunction, for example, the imposex of aquatic animals and the irregular estrous cycle of female mammals or spermatogenic disorders of male animals. Therefore, TPT should indeed be regarded as a major endocrine disruptor, which is essential for understanding the main toxic effects on different tissues and their pathogenic effects on endocrine, metabolism, neurological and reproductive dysfunction.

Di-(2-ethylhexyl) phthalate-induced tumor growth is regulated by primary cilium formation via the axis of H2O2 production-thymosin beta-4 gene expression

Di-(2-ethylhexyl) phthalate (DEHP) that is one of the most commonly used phthalates in manufacturing plastic wares regulates tumorigenesis. Thymosin beta-4 (TB4), an actin-sequestering protein, has been reported as a novel regulator to form primary cilia that are antenna-like organelles playing a role in various physiological homeostasis and pathological development including tumorigenesis. Here, we investigated whether DEHP affects tumor growth via primary cilium (PC) formation via the axis of TB4 gene expression and the production of reactive oxygen species (ROS). Tumor growth was increased by DEHP treatment that enhanced TB4 expression, PC formation and ROS production. The number of cells with primary cilia was enhanced time-dependently higher in HeLa cells incubated in the culture medium with 0.1% fetal bovine serum (FBS). The number of cells with primary cilia was decreased by the inhibition of TB4 expression. The incubation of cells with 0.1% FBS enhanced ROS production and the transcriptional activity of TB4 that was reduced by ciliobrevin A (CilioA), the inhibitor of ciliogenesis. ROS production was decreased by catalase treatment but not by mito-TEMPO, which affected to PC formation with the same trend. H₂O₂ production was reduced by siRNA-based inhibition of TB4 expression. H₂O₂ also increased the number of ciliated cells, which was reduced by siRNA-TB4 or the co-incubation with CilioA. Tumor cell viability was maintained by ciliogenesis, which was correlated with the changes of intracellular ATP amount rather than a simple mitochondrial enzyme activity. TB4 overexpression enhanced PC formation and DEHP-induced tumor growth. Taken together, data demonstrate that DEHP-induced tumor growth might be controlled by PC formation via TB4-H₂O₂ axis. Therefore, it suggests that TB4 could be a novel bio-marker to expect the risk of DEHP on tumor growth.

Disruption of fertility, placenta, pregnancy outcome, and multigenerational inheritance of hepatic steatosis by organotin exposure from contaminated seafood in rats

Early life exposure to endocrine-disrupting chemicals (EDCs) is an emerging risk factor for development of complications later in life and in subsequent generations. We previously demonstrated that exposure to the EDC organotin (OT), which is present in contaminated seafood, resulted in reproductive abnormalities in female rats. However, few studies have explored the effect of OT accumulation in seafood on pregnancy outcomes. This led us to consider the potential effects of the OT present in seafood on fertility, pregnancy, the placenta, and the offspring. In this investigation, we assessed whether exposure to the OT in contaminated seafood resulted in abnormal fertility and pregnancy features and offspring complications. OT in contaminated seafood (LNI) was administered to female rats, and their fertility, pregnancy outcomes, and fetal liver morphology were assessed. LNI caused abnormal fertility, a reduction in the total number of pups, and an increase in serum testosterone levels compared to controls. Furthermore, LNI exposure caused irregular uterine morphology with inflammation and fibrosis and led to a reduction in embryonic implantation. In pregnant rats, LNI caused abnormal lipid profiles and livers with steatosis features. LNI exposure also causes placental morpho-physiology disruption, a high presence of glycogen and inflammatory cells, and irregular lipid profiles. In addition, LNI exposure caused an increase in large amounts of carbohydrate and lipid delivery to the fetus via an increase in placental nutrient sensor protein expressions (GLUT1, IRβ/mTOR and Akt). In both genders of offspring, LNI exposure led to an increase in body weights, liver megakaryocytes, lipid accumulation, and oxidative stress (OS) levels. Collectively, these data suggest that OT exposure from contaminated seafood in female rats leads to reduced fertility, uterine implantation failure, pregnancy and placental metabolic outcome irregularities, offspring adiposity, liver steatosis, and an increase in OS. Furthermore, some of the effects of OT may be the result of obesogenic and multigenerational effects of OT in adult female rats.

The triphenyltin carboxylate derivative triphenylstannyl 2-(benzylcarbamoyl)benzoate impedes prostate cancer progression via modulation of Akt/FOXO3a signaling

Prostate cancer (PCa) incidence is surging in United States and other parts of the world. Synthetic and natural compounds have been explored as potential modulators of PI3K/Akt signaling that is known to drive PCa growth. Here, we evaluated the efficacy of a series of triphenyltin (IV) carboxylate derivatives against PCa. From this library, triphenylstannyl 2-(benzylcarbamoyl)benzoate (Ch-319) resulted in reduced viability and induction of cell cycle arrest in PTEN^-/- PC3M and PTEN^+/- DU145 cells. In parallel, downregulation of PI3K p85/p110 subunits, dephosphorylation of Akt-1 and increase in FOXO3a expression were observed. In silico studies indicated binding interactions of Ch-319 within the ATP binding site of Akt-1 at Met²⁸¹, Phe⁴⁴² and Glu²³⁴ residues. Elevated po-pulation of apoptotic cells, activation of Bax and reduced Bcl2 expression indicated apoptosis by Ch-319. Pre-sensitization of PCa cells with Ch-319 augmented the effect of cabazitaxel, a commonly used taxane in patients with castration-resistant PCa. Next, in a prostate-specific PTEN^p-/- mice, Ch-319 showed reduced weights of genitourinary apparatus as compared to DMSO treated controls. Histological studies indicated absence of neoplastic foci in Ch-319 treated prostates. Consistently, dephosphorylation of Akt-1, reduced expression of PRAS40 and androgen receptor and increase in FOXO3a were observed in treated group. Notably, no overt organ toxicity was noted in Ch-319 treated animals. Our studies identify Akt/FOXO3a signaling as a target of triphenyltin (IV) carboxylate Ch-319 and provide a molecular basis of its growth inhibitory effect in PCa cells. We propose that Ch-319 has the potential to be developed as an anticancer agent against PCa.

Occurrence, ecological and human health risks of phenyltin compounds in the marine environment of Hong Kong

Triphenyltin (TPT) has been known as one of the most toxic compounds being released into the marine environment by anthropogenic means. This study assessed the contamination statuses of TPT and its two major degradants, i.e., monophenyltin and diphenyltin, in seawater, sediment and biota samples from marine environments of Hong Kong, a highly urbanized and densely populated city, and evaluated their ecological and human health risks. The results showed that the Hong Kong's marine environments were heavily contaminated with these chemicals, especially for TPT. Concentration ranges of TPT in seawater, sediment and biota samples were 3.8-11.7 ng/L, 71.8-91.7 ng/g d.w., and 9.6-1079.9 ng/g w.w., respectively. As reflected by high hazard quotients (1.7-5.3 for seawaters; 46.1-59.0 for sediments), TPT exhibited high ecological and human health risks. Our results are essential for the future management and control of anthropogenic TPT use in antifouling paints and as biocides in agriculture.

Phenotypic Switching Resulting From Developmental Plasticity: Fixed or Reversible?

The prevalent view of developmental phenotypic switching holds that phenotype modifications occurring during critical windows of development are "irreversible" - that is, once produced by environmental perturbation, the consequent juvenile and/or adult phenotypes are indelibly modified. Certainly, many such changes appear to be non-reversible later in life. Yet, whether animals with switched phenotypes during early development are unable to return to a normal range of adult phenotypes, or whether they do not experience the specific environmental conditions necessary for them to switch back to the normal range of adult phenotypes, remains an open question. Moreover, developmental critical windows are typically brief, early periods punctuating a much longer period of overall development. This leaves open additional developmental time for reversal (correction) of a switched phenotype resulting from an adverse environment early in development. Such reversal could occur from right after the critical window "closes," all the way into adulthood. In fact, examples abound of the capacity to return to normal adult phenotypes following phenotypic changes enabled by earlier developmental plasticity. Such examples include cold tolerance in the fruit fly, developmental switching of mouth formation in a nematode, organization of the spinal cord of larval zebrafish, camouflage pigmentation formation in larval newts, respiratory chemosensitivity in frogs, temperature-metabolism relations in turtles, development of vascular smooth muscle and kidney tissue in mammals, hatching/birth weight in numerous vertebrates,. More extreme cases of actual reversal (not just correction) occur in invertebrates (e.g., hydrozoans, barnacles) that actually 'backtrack' along normal developmental trajectories from adults back to earlier developmental stages. While developmental phenotypic switching is often viewed as a permanent deviation from the normal range of developmental plans, the concept of developmental phenotypic switching should be expanded to include sufficient plasticity allowing subsequent correction resulting in the normal adult phenotype.

Genotoxicity and glucose tolerance induction by acetyltriethylcitrate, substitute plasticizer compared to di(2-ethylhexyl)phthalate

As di(2-ethylhexyl) phthalate (DEHP), one of phthalates, is classified as probable human carcinogens in EPA, acetyltriethyl citrate(ATEC), one of aliphatic esters, could be applied to DEHP substitute. ATEC is used as plasticizers in cosmetics and nail products. Here, we studied whether ATEC might have genotoxic potential and induce glucose tolerance as compared to DEHP. Genotoxicity was determined by Ames test with histidine-requiring Salmonella typhimurium (TA98, TA100, TA1535 and TA1537) and tryptophan-requiring Escherichia coli (WP2uvrA(pKM101)) strains, chromosomal aberration assay with Chinese hamster lung(CHL/IU) cells, and micronucleus test with bone marrow cells of CD-1 mice. The number of revertants was not significantly changed in Ames test. The frequency of cells with chromosome aberrations was less than 5% in ATEC- or DEHP-treated cells for 6 or 24 h. In addition, no statistically significant increase was observed for the incidence of micronucleated polychromatic erythrocytes (MNPCE) in polychromatic erythrocytes (PCE) and for the ratio of PCE among total erythrocytes at 24 or 48 h after the treatment of mice with ATEC or DEHP. In the meanwhile, blood glucose level (BGL) was increased by the treatment of mice with DEHP or ATEC for 5 consecutive days. Additional 7 days later, BGL by DEHP was recovered to normal level, but not that by ATEC. Then, taken together, our results suggest that ATEC could disrupt glucose metabolism under our experimental conditions. Therefore, although DEHP and ATEC may not be genotoxic, our data should be helpful for persons with the problem in glucose metabolism to choose products containing DEHP or ATEC.

Effects of exposure to triphenyltin (TPT) contaminant on sperm activity in adulthood of Calomys laucha exposed through breastfeeding

Triphenyltin (TPT) is an organotin compound (OT), primarily used in agriculture and in the composition of antifouling paints for ships worldwide. Studies have showed its effects as an endocrine disrupter in several organisms by preventing enzymatic expression and causing reproductive toxicity. This study aimed to evaluate the effects of exposure to TPT, via breastfeeding, on reproductive physiology in the Calomys laucha species. The experimental design was compound of five groups, two controls and three with different doses of TPT. Moreover, females were exposed by gavage to the TPT for 20 days, from the 1st day postpartum to the 21st postnatal day (PND). Then, the pups were euthanized and the kinetics, organelles, and biochemistry of the sperm were evaluated. The results presented a reduction in total motility in the groups exposed to TPT. Regarding cellular organelles analysis, a loss in membrane integrity was evidenced; the functionality of mitochondria showed diminution followed by increased acrosome reaction. In conclusion, the TPT causes alteration of the reproductive parameters, decreasing the activity and sperm quality in individuals exposed in the breastfeeding phase.

Melanoma in children, adolescents and young adults: anatomo-clinical features and prognostic study on 426 cases

PURPOSE

This study was conducted to determine the difference in anatomo-pathological and prognostic features of cutaneous melanoma in children, adolescents and young adults.

METHODS

This is a retrospective review on 383 young patients ≤ 39 years of age with cutaneous melanoma, in a period from 2006 to 2016 in Area Vasta Nord Ovest, Tuscany, Italy. We subdivided patients in three groups (children ≤ 14 years, adolescents 15-21 years, young adults 22-39 years). We correlated all the anatomo-pathological parameters with age groups.

RESULTS

We identified a total of 426 cases of cutaneous melanoma on an overall total of 383 patients. Mean age at diagnosis for all the patients ≤ 39 years of age was 31.2 years: in group A was 11.2 years, in group B 19.2 years and in group C 32.5 years. Incidence, in the subjects between 0 and 14 years, is 14 cases per million inhabitants, between 15 and 21 years of 145, and between 22 and 39 years of 394. Global incidence was 1.6 case per million for group A, 8.9 cases per million for group B, 105 cases per million for group C. No statistically significative correlation could be described for clinical parameters and age groups.

CONCLUSIONS

Incidence of melanoma in our casuistry results as the highest in the world. These data open new study for this kind of cancer.

The obesogen tributyltin induces abnormal ovarian adipogenesis in adult female rats

Tributyltin chloride (TBT) is an obesogen associated with various metabolic and reproductive dysfunctions after in utero exposure. However, few studies have evaluated TBT's obesogenic effect on adult ovaries. In this study, we assessed whether TBT's obesogenic effects resulted in adult ovarian adipogenesis and other reproductive abnormalities. TBT was administered to adult female Wistar rats, and their reproductive tract morphophysiology was assessed. We further assessed the ovarian mRNA/protein expression of genes that regulate adipogenesis. Rats exposed to TBT displayed abnormal estrous cyclicity, ovarian sex hormone levels, ovarian follicular development and ovarian steroidogenic enzyme regulation. Rats exposed to TBT also demonstrated abnormal ovarian adipogenesis with increased cholesterol levels, lipid accumulation, and PPARγ, C/EBP-β and Lipin-1 expression. A negative correlation between the ovarian PPARγ expression and aromatase expression was observed in the TBT rats. Furthermore, TBT exposure resulted in reproductive tract atrophy, inflammation, oxidative stress and fibrosis. Ovarian dysfunctions also co-occurred with the uterine irregularities. Abnormal ovarian adipogenic markers occurring after TBT exposure may be associated with uterine irregularities. A positive correlation between the ovarian cholesterol levels and uterine inflammation was observed in the TBT rats. These findings suggest that TBT leads to ovarian obesogenic effects directly by abnormal adipogenesis and/or indirectly through adult reproductive tract irregularities.

Di-(2-ethylhexyl) phthalate enhances melanoma tumor growth via differential effect on M1-and M2-polarized macrophages in mouse model

Phthalates are widely used as plasticizers that influence sexual and reproductive development. Here, we investigated whether di-(2-ethylhexyl) phthalate (DEHP) affects macrophage polarization that are associated with tumor initiation and progression. No changes were observed in LPS- or ConA-stimulated in vitro spleen B or T cell proliferation for 48 h, respectively. In contrast, macrophage functions were inhibited in response to DEHP for 12 h as judged by LPS-induced H₂O₂ and NO production and zymosan A-mediated phagocytosis. When six weeks old male mice were pre-exposed to 4.0 mg/kg DEHP for 21 days before the injection of B16F10 melanoma cells and post-exposed to 4.0 mg/kg DEHP for 7 days, tumor nodule formation and the changes in tumor volume were higher than those in control group. Furthermore, when male mice were intraperitoneally pretreated with DEHP for 3 or 4 weeks and peritoneal exudate cells (PECs) or bone marrow-derived macrophages (BMDMs) were incubated with lipopolysaccharide (LPS), the expression of COX-2, TNF-α, and IL-6 was reduced in DEHP-pretreated cells as compared with that in LPS-stimulated control cells. While the production of nitric oxide (NO) for 18 h was reduced by LPS-stimulated PECs and M1-type BMDMs, IL-4 expression was enhanced in LPS-stimulated BMDMs. When BMDMs were incubated with IL-4 for 30 h, arginase 1 for M2-type macrophages was increased in transcriptional and translational level. Data implicate that macrophages were differentially polarized by DEHP treatment, which reduced M1-polarzation but enhanced M2-polarization. Taken together, these data demonstrate that DEHP could affect in vivo immune responses of macrophages, leading to the suppression of their tumor-preventing ability. This suggests that individuals at high risk for tumor incidence should avoid long-term exposure to various kind of phthalate including DEHP.

Overview of the Pathophysiological Implications of Organotins on the Endocrine System

Organotins (OTs) are pollutants that are used widely by industry as disinfectants, pesticides, and most frequently as biocides in antifouling paints. This mini-review presents the main evidences from the literature about morphophysiological changes induced by OTs in the mammal endocrine system, focusing on the metabolism and reproductive control. Similar to other toxic compounds, the main effects with potential health risks to humans and experimental animals are not only related to dose and time of exposure but also to age, gender, and tissue/cell exposed. Regarding the underlying mechanisms, current literature indicates that OTs can directly damage endocrine glands, as well as interfere with neurohormonal control of endocrine function (i.e., in the hypothalamic-pituitary axis), altering hormone synthesis and/or bioavailability or activity of hormone receptors in the target cells. Importantly, OTs induces biochemical and morphological changes in gonads, abnormal steroidogenesis, both associated with reproductive dysfunctions such as irregular estrous cyclicity in female or spermatogenic disorders in male animals. Additionally, due to their role on endocrine systems predisposing to obesity, OTs are also included in the metabolism disrupting chemical hypothesis, either by central (e.g., accurate nucleus and lateral hypothalamus) or peripheral (e.g., adipose tissue) mechanisms. Thus, OTs should be indeed considered a major endocrine disruptor, being indispensable to understand the main toxic effects on the different tissues and its causative role for endocrine, metabolic, and reproductive dysfunctions observed.

Organotin Exposure and Vertebrate Reproduction: A Review

Organotin (OTs) compounds are organometallic compounds that are widely used in industry, such as in the manufacture of plastics, pesticides, paints, and others. OTs are released into the environment by anthropogenic actions, leading to contact with aquatic and terrestrial organisms that occur in animal feeding. Although OTs are degraded environmentally, reports have shown the effects of this contamination over the years because it can affect organisms of different trophic levels. OTs act as endocrine-disrupting chemicals (EDCs), which can lead to several abnormalities in organisms. In male animals, OTs decrease the weights of the testis and epididymis and reduce the spermatid count, among other dysfunctions. In female animals, OTs alter the weights of the ovaries and uteri and induce damage to the ovaries. In addition, OTs prevent fetal implantation and reduce mammalian pregnancy rates. OTs cross the placental barrier and accumulate in the placental and fetal tissues. Exposure to OTs in utero leads to the accumulation of lipid droplets in the Sertoli cells and gonocytes of male offspring in addition to inducing early puberty in females. In both genders, this damage is associated with the imbalance of sex hormones and the modulation of the hypothalamic-pituitary-gonadal axis. Here, we report that OTs act as reproductive disruptors in vertebrate studies; among the compounds are tetrabutyltin, tributyltin chloride, tributyltin acetate, triphenyltin chloride, triphenyltin hydroxide, dibutyltin chloride, dibutyltin dichloride, diphenyltin dichloride, monobutyltin, and azocyclotin.

Organotin Compounds Toxicity: Focus on Kidney

Organotin compounds (OTs) are synthetic persistent organometallic xenobiotics widely used in several commercial applications. They exert well-described harmful effects in brain, liver, adipose tissue, and reproductive organs, as they are endocrine-disrupting chemicals (EDCs), but the effects in the kidneys are less known. The kidneys are especially vulnerable to environmental contaminants because they are a metabolizing site of xenobiotics, therefore, pollutants can accumulate in renal tissue, leading to impaired renal function and to several renal abnormalities. Individuals chronically exposed to OTs present a threefold increase in the prevalence of kidney stones. These compounds can directly inhibit H⁺/K⁺-ATPase in renal intercalated cells, resulting in hypokalemia, renal tubular acidity, and increased urinary pH, which is a known risk factor for kidney stones formation. OTs effects are not only limited to induce nephrolithiasis, its nephrotoxicity is also due to increased reactive oxygen species (ROS). This increase leads to lipid peroxidation, abnormal cellular function, and cell death. Combined, the enzymatic and non-enzymatic antioxidant defense systems become deficient and there is a consequent uncontrolled generation of ROS that culminates in renal tissue damage. Still, few epidemiological and experimental studies have reported renal impact correlated to OTs exposure. This lack of investigation of the complete effect of OTs in renal function and structure led us to perform this review reporting the main researches about this subject.

Effects of triphenyltin on reproduction in Japanese medaka (Oryzias latipes) across two generations

Triphenyltin (TPT) is an organotin compound used in marine anti-fouling coatings to prevent the attachment and growth of marine organisms, and it has negative effects on aquatic organisms. TPT is still detected at low concentrations, although its use has been prohibited at least in the European Community and is restricted in Japan as well. Studies using Japanese medaka (Oryzias latipes) indicate that TPT has the potential to inhibit reproduction. Although TPT is detected in many aquatic ecosystems, the multi-generational impact of TPT remains unknown. We investigated the two-generational effects of TPT on Japanese medaka and examined the relationships of several such effects between the F0 and F1 generations. Suppression of fecundity was observed in both generations, and fertility and growth were inhibited in the F1 generation. Moreover, delayed hatching and lower hatchability were observed in F1 embryos. Importantly, the value of the lowest observed effect concentration (LOEC) for these influences in F1 was lower than that in F0: that is, the LOEC values of fecundity and mortality were 3.2μg/L in the F0 generation and 1.0μg/L in the F1 generation. Fertility was not affected by TPT in F0, whereas it was significantly suppressed in the 1.0μg/L-exposure group of the F1 generation. Our results provide the first evidence of the effects of TPT on reproduction in a teleost fish across two generations, highlighting the concern that TPT could affect reproduction and mortality at decreasing concentrations in temporally overlapping generations.

Tributyltin chloride induces renal dysfunction by inflammation and oxidative stress in female rats

Tributyltin chloride (TBT) is an organometallic pollutant that is used as a biocide in antifouling paints. TBT induces several toxic and endocrine-disrupting effects. However, studies evaluating the effects of TBT on renal function are rare. This study demonstrates that TBT exposure is responsible for improper renal function as well as the development of abnormal morphophysiology in mammalian kidneys. Female rats were treated with TBT, and their renal morphophysiology was assessed. Morphophysiological abnormalities such as decreased glomerular filtration rate and increased proteinuria levels were observed in TBT rats. In addition, increases in inflammation, collagen deposition and α-smooth muscle actin (α-SMA) protein expression were observed in TBT kidneys. A disrupted cellular redox balance and apoptosis in kidney tissue were also observed in TBT rats. TBT rats demonstrated reduced serum estrogen levels and estrogen receptor-α (ERα) protein expression in renal cortex. Together, these data provide in vivo evidence that TBT is toxic to normal renal function and that these effects may be associated with renal histopathology complications, such as inflammation and fibrosis.

Acute iron overload leads to hypothalamic-pituitary-gonadal axis abnormalities in female rats

Iron plays a critical role in a mammal's physiological processes. However, iron tissue deposits have been shown to act as endocrine disrupters. Studies that evaluate the effect of acute iron overload on hypothalamic-pituitary-gonadal (HPG) axis health are particularly sparse. This study demonstrates that acute iron overload leads to HPG axis abnormalities, including iron accumulation and impairment in reproductive tract morphology. Female rats were treated with iron-dextran (Fe rats) to assess their HPG morphophysiology. The increasing serum iron levels due to iron-dextran treatment were positively correlated with higher iron accumulation in the HPG axis and uterus of Fe rats than in control rats. An increase in the production of superoxide anions was observed in the pituitary, uterus and ovary of Fe rats. Morphophysiological reproductive tract abnormalities, such as abnormal ovarian follicular development and the reduction of serum estrogen levels, were observed in Fe rats. In addition, a significant negative correlation was obtained between ovary superoxide anion and serum estrogen levels. Together, these data provide in vivo evidence that acute iron overload is toxic for the HPG axis, a finding that may be associated with the subsequent development of the risk of reproductive dysfunction.

Sexual maturation and fertility of mice exposed to triphenyltin during prepubertal and pubertal periods

This study investigated the effects of pre- and peripubertal exposure (PND 15-45) to triphenyltin hydroxide (TPT: 0, 1.875, 3.75, 7.5 and 15 mg/kg bw/d po) on mouse sexual maturation and fertility. Half of the mice were euthanized on PND 46 and the remaining mice were submitted to fertility tests on PND 65-75. TPT caused a transient decrease of weight gain at 3.75 mg/kg bw/d, and deaths and body weight deficits at higher doses. Delays of testes descent (TD), vaginal opening (VO) and first estrus (FE) occurred at doses ≥3.75 (TD) and ≥7.5 mg/kg bw/d (VO, FE), respectively. Body weight on the days of TD, VO and FE did not differ among groups. TPT at doses ≥3.75 mg/kg decreased sperm and spermatid counts at the end of treatment (PND 46) but no alteration was noted later on PND 75. Testicular histopathology (PND 46) showed a dose-dependent reduction of seminiferous tubules diameter, a greater degree of vacuolation in Sertoli cells and germ cell degeneration and necrosis in TPT-treated mice. TPT did not affect the outcome of fertility tests. Study-derived NOAEL was 1.875 mg TPT/kg bw/d for males and 3.75 mg TPT/kg bw/d for females. The detrimental effects of TPT on spermatogenesis were reversed after treatment discontinuation.

Effects of perinatal exposure to low doses of tributyltin chloride on pregnancy outcome and postnatal development in mouse offspring

Tributyltin (TBT), an endocrine-disrupting chemical, is well known to induce imposex in female gastropods. In this study, we assessed the effects of low doses of tributyltin chloride (TBTCl) on dams and their offspring. Pregnant mice were administered by gavage with 0, 1, 10, or 100 μg TBTCl/kg body weight/day from day 6 of pregnancy through the period of lactation. There were no TBT treatment-related deaths or clinical signs of toxicity for dams, and no treatment-related effects on body weight, litter sizes, gestational length of dams, and sex ratio, lactational body weight, postnatal survival, age at eruption of incisors, and eye opening of pups. However, at 100 μg/kg, TBTCl retarded the testes descent of male offspring. Behavioral tests showed a significant delay in cliff-drop aversion response in offspring of 10 and 100 μg/kg groups, but no significant difference in the righting reflex between control and TBT-exposed offspring was detectable. These results indicate that neurobehavioral toxicity seems to be one sensitive indicator to assess the risk of low doses of TBT.

Speciation and degradation of triphenyltin in typical paddy fields and its uptake into rice plants

Triphenyltin (TPhT) is a biocide used worldwide in agriculture, especially in rice crop farming. The distribution and dissipation of TPhT in rice fields, as well as uptake of TPhT and other phenyltin compounds (monophenyltin, MPhT, and diphenyltin, DPhT) is still unknown at present. In this study, speciation analysis of phenyltin compounds was carried out in soil and water from a rice field where TPhT was applied during rice seeding according to legal application rates in Brazil. The results indicate the degradation of biocide and distribution of tin species into soil and water. To evaluate whether TPhT is taken up by plants, rice plants were exposed to three different TPhT application rates in a controlled mesocosm during 7 weeks. After this period, tin speciation was determined in soil, roots, leaves, and grains of rice. Degradation of TPhT was observed in soil, where DPhT and MPhT were detected. MPhT, DPhT, and TPhT were also detected in the roots of plants exposed to all TPhT application rates. Only TPhT was detected in leaves and at relatively low concentration, suggesting selective transport of TPhT in the xylem, in contrast to DPhT and MPhT. Concentration of phenyltin species in rice grains was lower than the limit of detection, suggesting that rice plants do not have the capability to take up TPhT from soil and transport it to the grains.

Sex-dependent aromatase activity in rat offspring after pre- and postnatal exposure to triphenyltin chloride

Triphenyltin (TPT) is an organotin compound (OTC) previously widely used as an antifouling agent in paints applied in the marine environment, a fungicide, and as an agricultural pesticide. In female aquatic invertebrates, certain OTCs induce the so-called imposex, an abnormal induction of male sex characteristics. OTC-induced environmental endocrine disruption also occurs in fish and mammals and a number of in vivo and in vitro studies have argued that OTCs may act through inhibition of the aromatase enzyme. In vivo studies supporting the aromatase inhibition hypothesis in mammals are lacking. Recently, the causal relationship between inhibition of aromatase and imposex was questioned, suggesting aromatase independent mechanisms of action for this phenomenon. We conducted a comprehensive investigation to identify the most sensitive window of exposure to TPTCl and to examine the effects of pre- and postnatal exposure on postnatal development in rats. The results on brain and gonadal aromatase activity obtained from offspring of dams exposed to 2 mg TPTCl/kg bw are reported here. Female and male offspring rats were exposed to 2 mg TPTCl/kg bw/d in utero from gestation day 6 through lactation until weaning on PND 21, or from gestation day 6 until termination at adulthood. Male offspring were sacrificed from PND 58 and female offspring at first estrus after PND 58. Pre- and postnatal TPT exposure clearly affected brain and gonadal aromatase activity in a sex-dependent fashion. While brain aromatase activity was significantly increased on PND 21 and at adulthood in female offspring, male offspring exhibited a significant decrease in brain aromatase activity only at adulthood. Ovarian aromatase activity was unaffected at both time points investigated. In contrast, testicular aromatase activity was significantly increased in males on PND 21 and significantly decreased at adulthood independent from the duration of treatment. The results of the present study confirm our previously reported observations regarding sex-dependent differences in sexual development after TPT exposure with the male rat being more susceptible to disturbances through this endocrine active compound than the female. We conclude that TPT administered during the particularly vulnerable period of development can affect aromatase activity in rats.

Postnatal development and fertility of offspring from mice exposed to triphenyltin (fentin) hydroxide during pregnancy and lactation

Fentin or triphenylthin (TPT) is an organotin compound (OTC) widely used as an agricultural fungicide and miticide. It is well known that TPT exerts adverse effects on the reproductive and immune systems and may disrupt the endocrine system, raising concerns regarding the risks posed by exposure to this metal on environmental and human health. In this study the effects of maternal exposure to TPT at doses of control (0), 1.875, 3.75, or 7.5 mg/kg body weight/d, po, were examined during gestation and lactation on offspring growth, organ weights, and fertility. Except for a significant liver enlargement at the highest dose, TPT produced no maternal toxicity. Increased neonatal mortality (death of 3 entire litters from a total of 18 treated litters) was noted at 7.5 mg/kg. Pup body weight at birth was significantly reduced at all dose levels, but no marked weight loss was found on postnatal day (PND) 5 and thereafter. Offspring maturation (ear unfolding, incisor eruption, vagina opening, and testes descent) and fertility in adulthood were not significantly affected by maternal exposure to TPT. In conclusion, data provided by this study indicate that maternal treatment with TPT during pregnancy and lactation delayed prenatal growth but did not impair postnatal development and fertility in exposed offspring in adulthood.