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

Plasma metals, genetic risk, and rapid kidney function decline among type 2 diabetes

BACKGROUND

Rapid kidney function decline (RKFD) is a main clinical feature of early chronic kidney disease (CKD) in type 2 diabetes (T2D). Environmental and genetic factors influencing RKFD remain inadequately elucidated.

OBJECTIVES

This study aimed to examine the associations of metals with RKFD among T2D and to further investigate the effect of metal mixtures on RKFD with the modifying effect of genetic susceptibility.

METHODS

This study included 2209 people with T2D (1942 had genotyping data) free of CKD at baseline from the Dongfeng-Tongji cohort. We used inductively coupled plasma-mass spectrometry (ICP-MS) to measure 23 metals in baseline plasma. Using elastic net (ENET), multivariate logistic regression, and Bayesian kernel machine regression (BKMR) model, we examined independent associations of multiple metals with RKFD. We calculated the environmental risk score (ERS) to assess the effects of metal mixtures on RKFD and the genetic risk score (GRS) to assess genetic susceptibility. RKFD was defined as estimated glomerular filtration rate (eGFR) loss > 3 mL/min/1.73 m2/year.

RESULTS

During a median of 9.8 years follow-up, 262 participants developed RKFD. Aluminum, vanadium, zinc, selenium, rubidium, tin, barium, and tungsten were screened from ENET. In multivariate logistic models, vanadium, selenium, and tungsten were negatively associated with RKFD, while zinc, tin, and rubidium were positively associated. The BKMR showed a nonlinear association of vanadium and rubidium with RKFD and interactions between metals (barium‑vanadium, barium‑rubidium). The ERS was positive associated with RKFD (per SD increase in ERS, OR = 1.94, 95% CI: 1.66, 2.27). No significant interaction between ERS and GRS was observed on RKFD, however, participants in the highest ERS and GRS group had the highest RKFD risk.

CONCLUSION

Vanadium and rubidium were associated with RKFD in T2D. Metal mixtures was associated with an increased risk of RKFD in T2D, particularly in those at high genetic risk.

Subacute exposure to a mixture of tributyltin plus mercury impairs reproductive axis function, exacerbating premature ovarian insufficiency features and reducing fertility in female rats

Tributyltin (TBT) and mercury (Hg) are endocrine-disrupting chemicals that individually cause reproductive complications. However, the reproductive consequences of exposure to a mixture of TBT plus Hg are not well known. We hypothesized that exposure to a mixture of TBT plus Hg would alter hypothalamic-pituitary-gonadal (HPG) axis function. Female rats were exposed to this mixture daily for 15 days, after which chemical accumulation in the tissues, morphology, hormone levels, inflammation, fibrosis, and protein expression in the reproductive organs were assessed. Increases in tin (Sn) and Hg levels were detected in the serum, HPG axis, and uterus of TBT-Hg rats. TBT-Hg rats exhibited irregular estrous cycles. TBT-Hg rats showed an increase in gonadotropin-releasing hormone (GnRH) protein expression and follicle-stimulating hormone (FSH) levels and a reduction in luteinizing hormone (LH) levels. Reduced ovarian reserve, antral follicles, corpora lutea (CL) number, and estrogen levels and increased atretic and cystic follicles were found, suggesting that TBT-Hg exposure exacerbated premature ovarian insufficiency (POI) features. Furthermore, TBT-Hg rats exhibited increased ovarian mast cell numbers, expression of the inflammatory markers IL-6 and collagen deposition. Apoptosis and reduced gland number were observed in the uteri of TBT-Hg rats. A reduction in the number of pups/litter for 90 days was found in TBT-Hg rats, suggesting impaired fertility. Strong negative correlations were found between serum and ovarian Sn levels and ovarian Hg levels and ovarian reserve and CL number. Collectively, these data suggest that TBT plus Hg exposure leads to abnormalities in the HPG axis, exacerbating POI features and reducing fertility in female rats.

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.

Protective effects of sulforaphane on inflammation, oxidative stress and intestinal dysbacteriosis induced by triphenyltin in Cyprinus carpio haematopterus

The purpose of this experiment was to study the mitigation effect of sulforaphane (SFN) on fish toxicological damage caused by triphenyltin (TPT) pollution. A total of 320 healthy fish (56.9 ± 0.4g) were randomly placed into four groups, each with four duplicates. The control group was fed the basal diet, the TPT group was exposed to 10 ng/L TPT on the basis of the control group, the SFN group was fed a diet supplemented with 10 mg/kg SFN, the SFN + TPT group was exposed to 10 ng/L TPT on the basis of the SFN group. Each tank had 20 fish and the breeding lasted for 8 weeks. The present study found that the antioxidant enzyme activity in the TPT group was significantly lower than that of the control group (P < 0.05). In addition, compared with the control group, the mRNA expression of pro-inflammatory factors (IL-6, TNF-α) were significantly induced, and the anti-inflammatory factor genes (IL-10, TGF) were significantly inhibited (P < 0.05) in TPT group. SFN relieved the changes of inflammatory factors caused by TPT, ameliorated oxidative stress, improved antioxidant enzyme (include SOD, CAT, GSH, GPx) activities (P < 0.05). 16s RNA analysis indicated that exposure to TPT caused changes in intestinal microflora. The results of the study showed that after exposure to TPT, some beneficial genera of bacteria in the gut of Rhizobiaceae, Bdellovibrio and Candidatus Alysiosphaera were decreased. The bacteria associated with intestinal inflammation including Propionibacterium, Rubrobacter, Anaerorhabdus_furcosa_group, Rikenellaceae and Eubacterium_brachy were upregulated. However, the SFN treatment group significantly down-regulated the above five inflammation-related bacteria. The above results indicated that TPT caused oxidative stress and inflammation in fish intestines, changed the intestinal microflora, and dietary SFN could improve antioxidant status, regulate inflammation and intestinal health. Therefore, SFN is a promising diet additive for improving fish damage caused by TPT contamination.

Environmental Health and Toxicology: Immunomodulation Promoted by Endocrine-Disrupting Chemical Tributyltin

Tributyltin (TBT) is an environmental contaminant present on all continents, including Antarctica, with a potent biocidal action. Its use began to be intensified during the 1960s. It was effectively banned in 2003 but remains in the environment to this day due to several factors that increase its half-life and its misuse despite the bans. In addition to the endocrine-disrupting effect of TBT, which may lead to imposex induction in some invertebrate species, there are several studies that demonstrate that TBT also has an immunotoxic effect. The immunotoxic effects that have been observed experimentally in vertebrates using in vitro and in vivo models involve different mechanisms; mainly, there are alterations in the expression and/or secretion of cytokines. In this review, we summarize and update the literature on the impacts of TBT on the immune system, and we discuss issues that still need to be explored to fill the knowledge gaps regarding the impact of this endocrine-disrupting chemical on immune system homeostasis.

Environmentally relevant dose of the endocrine disruptor tributyltin disturbs redox balance in female thyroid gland

Tributyltin (TBT) is an endocrine disruptor used as a biocide in nautical paints. Even though many TBT effects in marine species are known, data in mammals are scarce, especially regarding the thyroid gland. The present study aimed to evaluate the effect of a subchronic exposure to TBT on thyroid oxidative stress of female Wistar rats. Rats received vehicle (control group), 200 or 1000 ng TBT/kg body weight/day for 40 days. After euthanasia, one part of the thyroids were collected in order to assess iodide uptake; activity and/or mRNA expression of thyroperoxidase (TPO) and dual oxidases (DUOXs); activity and/or mRNA expression of catalase, glutathione peroxidase, superoxide dismutase and NADPH oxidase 4 (CAT, GPx, SOD and NOX4); 4-hydroxynonenal (4-HNE) expression and total thiol groups levels; and mRNA expression of estrogen receptors alpha and beta (ERα and ERβ). The remaining part of the thyroid was processed for morphological analysis of estrogen receptor alpha (ERα) and for collagen deposition. Iodide uptake was not changed with treatments. TPO activity and expression were increased in the TBT1000 group (259.81% and 95.17%). The activity, but not mRNA, of CAT (17.36% TBT200; 27.10% TBT1000) and GPx (29.24% TBT200; 28.97% TBT1000) were decreased by TBT. SOD and NADPH oxidase activity, as well as thiol group and 4-HNE levels remained unchanged. Interstitial collagen deposition increased in the TBT200 group (39.54%). The mRNA expression of ERα increased in TBT-treated rats (44.87% TBT200; 36.43% TBT1000), while protein expression was increased but not reaching significance (TBT1000, p = 0.056) by TBT. Therefore, our results show that TBT increases TPO expression and reduces antioxidant enzyme activities in the thyroid gland leading to oxidative stress. Some of these effects could be mediated by the ERα pathway.

Tributyltin Exposure Is Associated With Recognition Memory Impairments, Alterations in Estrogen Receptor α Protein Levels, and Oxidative Stress in the Brain of Female Mice

Tributyltin (TBT) is a persistent organometallic pollutant widely used in several agricultural and industrial processes. TBT exposure is associated with various metabolic, reproductive, immune, and cardiovascular abnormalities. However, few studies have evaluated the effects of TBT on behavior. In the present study, we aimed to investigate whether TBT exposure results in oxidative, neuroendocrine, and behavioral alterations. TBT was administered to adult female mice (250, 500, or 750 ng/kg/day or veh for 14 days), and their recognition memory was assessed. We have also evaluated estrogen receptor (ER)α protein expression and oxidative stress (OS) in brain areas related to memory, as well as the correlation between them. A reduction in short- and long-term recognition memory (STM and LTM) performance, as well as in total exploration time was observed in TBT mice. Reduced ERα protein expression was observed in the prefrontal cortex (PFC) and hippocampus of TBT mice, while an increase in TBARS concentration was observed in the PFC of treated animals. Collectively, these data suggest that TBT exposure impairs recognition memory in female mice as a result of, at least in part, its toxicological effects on ERα expression and OS in specific brain areas related to memory.

Evaluation of the effects produced by subacute tributyltin administration on vascular reactivity of male wistar rats

Tributyltin chloride (TBT) is an organotin compound widely used in several high biocides for agroindustrial applications, such as fungicides, and marine antifouling paints leading to endocrine disrupting actions, such as imposex development in mollusks. In female rats, TBT has been shown to promote ovarian dysfunction, reduction of estrogen protective effect in the vascular morphophysiology, at least in part by oxidative stress consequences. Estrogen causes coronary endothelium-dependent and independent vasodilation. However, the TBT effects on cardiovascular system of male rats are not fully understood. The aim of this study was to evaluate the effects of subacute TBT exposure in aorta vascular reactivity from male wistar rats. Rats were randomly divided into three groups: control (C), TBT 500 ng/kg/day and TBT 1000 ng/kg/day. TBT was administered daily for 30 days by oral gavage. We found that TBT exposure enhanced testosterone serum levels and it was also observed obesogenic properties. TBT exposure evoked an increase in endothelium-dependent and independent phenylephrine-induced contraction, associated to an inhibition in eNOS activity. On the other hand, it was observed an enhancement of iNOS and NF-kB protein expression. We also observed an increase in oxidative stress parameters, such as superoxide dismutase (SOD) and catalase expression, and also an increase in malondialdehyde production. Finally, TBT exposure produced aortic intima-media thickness. Taken together, these data suggest a potential cardiovascular toxicological effect after subacute TBT exposure in male rats.

The ameliorative effect of Moringa oleifera oil on tributyltin-induced brain toxicity in albino rats

Tributyltin (TBT) is an organotin compound widely used as a biocide in antifouling paints. Moringa oleifera oil (MOO) has a promising antioxidant potential, which necessitates further exploration. This study was conducted to investigate the potential protective effect of MOO against TBT-induced brain toxicity. The 30 rats were grouped into five groups (six each), Group I negative control, Group II positive control (vehicle), Group III MOO (5 ml/kg body weight [b.wt.]), Group IV TBT (10 mg/kg b.wt.), and Group V TBT & MOO. All treatments were given orally for 28 days. Thereafter, brains were exposed to oxidative stress and neurological parameters analyses. Histopathological and immunohistochemical (caspase-3, Bax, Bcl-2) examinations were also carried out. In rats administered TBT, increased malondialdehyde level, decreased reduced glutathione, and low total antioxidant capacity levels were in support of oxidative stress mechanism. Neurotoxicity was indicated by high nitric oxide level and increased acetylcholinestrase activity. Along with the histopathological alterations, the dysregulated expression of caspase-3, Bax, and Bcl-2 were indicative of the apoptotic mechanism mediated by TBT. Co-administration of MOO with TBT ameliorated the aforementioned toxic effects. In conclusion, TBT causes brain toxicity via oxidative, nitrosative, and apoptotic mechanisms. MOO demonstrates protective effect against TBT-induced brain toxicity mostly via potent antioxidant and antiapoptotic properties.

Subchronic and Low Dose of Tributyltin Exposure Leads to Reduced Ovarian Reserve, Reduced Uterine Gland Number, and Other Reproductive Irregularities in Female Mice

Tributyltin (TBT) chloride is an endocrine disrupting chemical associated with reproductive complications. Studies have shown that TBT targets the reproductive tract, impairing ovarian folliculogenesis, and uterine morphophysiology. In this investigation, we assessed whether subchronic and low dose of TBT exposure results in abnormal ovarian follicular reserve and other irregularities in female mice. TBT was administered to female mice (500 ng/kg/day for 12 days via gavage), and reproductive tract morphophysiology was assessed. We further assessed reproductive tract inflammation and oxidative stress. Improper functioning of the reproductive tract in TBT mice was observed. Specifically, irregular estrous cyclicity and abnormal ovarian morphology coupled with reduction in primordial and primary follicle numbers was observed, suggesting ovarian reserve depletion. In addition, improper follicular development and a reduction in antral follicles, corpora lutea, and total healthy ovarian follicles together with an increase in cystic follicles were apparent. Evidence of uterine atrophy, reduction in endometrial gland number, and inflammation and oxidative stress were seen in TBT mice. Further, strong negative correlations were observed between testosterone levels and primordial, primary, and total healthy ovarian follicles. Thus, these data suggest that the subchronic and low dose of TBT exposure impaired ovarian follicular reserve, uterine gland number, and other reproductive features in female mice.

The Effects of High-Protein Diet and Resistance Training on Glucose Control and Inflammatory Profile of Visceral Adipose Tissue in Rats

High-protein diets (HPDs) are widely accepted as a way to stimulate muscle protein synthesis when combined with resistance training (RT). However, the effects of HPDs on adipose tissue plasticity and local inflammation are yet to be determined. This study investigated the impact of HPDs on glucose control, adipocyte size, and epididymal adipose inflammatory biomarkers in resistance-trained rats. Eighteen Wistar rats were randomly assigned to four groups: normal-protein (NPD; 17% protein total dietary intake) and HPD (26.1% protein) without RT and NPD and HPD with RT. Trained groups received RT for 12 weeks with weights secured to their tails. Glucose and insulin tolerance tests, adipocyte size, and an array of cytokines were determined. While HPD without RT induced glucose intolerance, enlarged adipocytes, and increased TNF-α, MCP-1, and IL1-β levels in epididymal adipose tissue (p < 0.05), RT diminished these deleterious effects, with the HPD + RT group displaying improved blood glucose control without inflammatory cytokine increases in epididymal adipose tissue (p < 0.05). Furthermore, RT increased glutathione expression independent of diet (p < 0.05). RT may offer protection against adipocyte hypertrophy, pro-inflammatory states, and glucose intolerance during HPDs. The results highlight the potential protective effects of RT to mitigate the maladaptive effects of HPDs.

Tributyltin Alters Calcium Levels, Mitochondrial Dynamics, and Activates Calpains Within Dorsal Root Ganglion Neurons

Tributyltin (TBT) remains a global health concern. The primary route of human exposure to TBT is either through ingestion or skin absorption, but TBT's effects on the peripheral nervous system have still not been investigated. Therefore, we exposed in vitro sensory dorsal root ganglion (DRG) neurons to TBT at a concentration of 50-200 nM, which is similar to the observed concentrations of TBT in human blood samples. We observed that TBT causes extensive axon degeneration and neuronal death in the DRG neurons. Furthermore, we discovered that TBT causes an increase in both cytosolic and mitochondrial calcium levels, disrupts mitochondrial dynamics, decreases neuronal ATP levels, and leads to the activation of calpains. Additional experiments demonstrated that inhibition of calpain activation prevented TBT-induced fragmentation of neuronal cytoskeletal proteins and neuronal cell death. Thus, we conclude that calpain activation is the key executioner of TBT-induced peripheral neurodegeneration.

Bone Disruption and Environmental Pollutants

BACKGROUND

Endocrine Disrupting Chemicals (EDCs) are ubiquitous and may significantly contribute in environmental pollution, thus contaminating humans and wildlife. Environmental pollutants could interfere with bone homeostasis by means of different mechanisms, which include hormonal imbalance, direct osteoblasts toxicity and enanchment of osteoclasts activity, thus leading to osteopenia or osteoporosis. Among these, bisphenols, dioxins, polycyclic aromatic hydrocarbons, polychlorobiphenyls, poly- and perfluoroalkyls, phthalates, parabens, organotins and cadmium may play a role in bone distuption.

METHODS

PubMed/MEDLINE, ISI-web of knowledge and Google scholar databases were searched for medical subject headings terms and free-text word related to the aforementioned classes of chemicals and bone metabolism and remodelling for better clarifying and understanding the main mechanisms of bone disruption.

RESULTS

Several of EDCs act as xenoestrogens. Considering that estrogens play a significant role in regulating bone remodeling, most of these chemicals generate hormonal imbalance with possible detrimental consequences on bone tissue structure and its mechanical and non-mechanical properties.

DISCUSSION

A lot of evidences about bone distruptors came from in vitro studies or animal models, and conduct to equivocal results. In addition, a few data derived form humans and most of these data focused on the impact of EDCs on bone mineral density without considering their influence on long-term fracture risk. Moreover, it should be taken into account that humans are exposed to a mixture of EDCs and the final effect on bone metabolism might be the result of either a synergism or antagonist effects among them. Age of first exposure, cumulative dose exposure over time, and the usually observed non-monotonic dose-response curve for EDCs should be considered as other important variable influencing the final effect on bone metabolism.

CONCLUSION

Taking into account these variables, observational studies are needed to better analyze this issue both for echological purpose and to preserve bone health.

ROS-Dependent ER Stress and Autophagy Mediate the Anti-Tumor Effects of Tributyltin (IV) Ferulate in Colon Cancer Cells

Organotin compounds represent potential cancer therapeutics due to their pro-apoptotic action. We recently synthesized the novel organotin ferulic acid derivative tributyltin (IV) ferulate (TBT-F) and demonstrated that it displays anti-tumor properties in colon cancer cells related with autophagic cell death. The purpose of the present study was to elucidate the mechanism of TBT-F action in colon cancer cells. We specifically show that TBT-F-dependent autophagy is determined by a rapid generation of reactive oxygen species (ROS) and correlated with endoplasmic reticulum (ER) stress. TBT-F evoked nuclear factor erythroid-2 related factor 2 (Nrf2)-mediated antioxidant response and Nrf2 silencing by RNA interference markedly increased the anti-tumor efficacy of the compound. Moreover, as a consequence of ROS production, TBT-F increased the levels of glucose regulated protein 78 (Grp78) and C/EBP homologous protein (CHOP), two ER stress markers. Interestingly, Grp78 silencing produced significant decreasing effects on the levels of the autophagic proteins p62 and LC3-II, while only p62 decreased in CHOP-silenced cells. Taken together, these results indicate that ROS-dependent ER stress and autophagy play a major role in the TBT-F action mechanism in colon cancer cells and open a new perspective to consider the compound as a potential candidate for colon cancer treatment.

Evaluation of induced biological effects in rats by continuous and natural gamma radiation using a physical simulator

PURPOSE

The effects of radioactivity on human health have been debated for many years but there are still important gaps that need to be addressed especially related to the effects of high natural background radiation on the local population. The beach of Meaípe, in the city of Guarapari (Brazil), emits natural gamma radiation due to the presence of monazite sands. We aimed to investigate the effects of gamma radiation doses on the biological system of wistar rats using a physical simulator of gamma radiation designed using Meaípe monazite sands.

METHODS

Female Wistar rats were divided into three groups, submitted to no radiation (control group) and to continuous radiation levels, one of very high level (20 μSv h^-1) and another of high level (3.6 μSv h^-1). The three group of animals were monitored weekly for 3 months and at the end of the study the animals were sacrificed, and the organs were extracted and weighed for anthropometric, oxidative stress and histological evaluations.

RESULTS

Exposure to radiation released by the monazite sands did not cause anthropometric alterations or blood pressure change in the animals. Similarly, there was no change in the quantification of ovarian follicles between the radiation groups and the control group. There was no difference in the oxidative stress quantification by the thiobarbituric acid reactive substance and advanced oxidation protein product methods in the ovaries. There were no evidenced damages in the structure of the renal tissue. It was observed the presence of granulomas in the hepatic tissue and alterations in the nuclei of the hepatocytes.

CONCLUSIONS

Our results suggest that the continuous exposure of females rats to 3.6 and 20 μSv h^-1 doses of gamma radiation slightly affected the hepatic tissue, but did not alter the histological parameters in the kidneys and ovaries and oxidative stress.

Physical Exercise Exacerbates Acute Kidney Injury Induced by LPS via Toll-Like Receptor 4

Introduction: Lipopolysaccharide (LPS) is a systemic response-triggering endotoxin, which has the kidney as one of its first targets, thus causing acute injuries to this organ. Physical exercise is capable of promoting physiological alterations and modulating inflammatory responses in the infectious process through multiple parameters, including the toll-like receptor (TLR)-4 pathway, which is the main LPS signaling in sepsis. Additionally, previous studies have shown that physical exercise can be both a protector factor and an aggravating factor for some kidney diseases. This study aims at analyzing whether physical exercise before the induction of LPS endotoxemia can protect kidneys from acute kidney injury.

Methods: C57BL/6J male mice, 12 weeks old, were distributed into four groups: (1) sedentary (control, N = 7); (2) sedentary + LPS (N = 7); (3) trained (N = 7); and (4) trained + LPS (N = 7). In the training groups, the animals exercised 5×/week in a treadmill, 60 min/day, for 4 weeks (60% of max. velocity). Sepsis was induced in the training group by the application of a single dose of LPS (5 mg/kg i.p.). Sedentary animals received LPS on the same day, and the non-LPS groups received a saline solution instead. All animals were euthanized 24 h after the administration of LPS or saline.

Results: The groups receiving LPS presented a significant increase in serum urea (p < 0.0001) and creatinine (p < 0.001) concentration and renal gene expression of inflammatory markers, such as tumor necrosis factor alpha and interleukin-6, as well as TLRs. In addition, LPS promoted a decrease in reduced glutathione. Compared to the sedentary + LPS group, trained + LPS showed overexpression of a gene related to kidney injury (NGAL, p < 0.01) and the protein levels of LPS receptor TLR-4 (p < 0.01). Trained + LPS animals showed an expansion of the tubulointerstitial space in the kidney (p < 0.05) and a decrease in the gene expression of hepatic AOAH (p < 0.01), an enzyme involved in LPS clearance.

Conclusion: In contrast to our hypothesis, training was unable to mitigate the renal inflammatory response caused by LPS. On the contrary, it seems to enhance injury by accentuating endotoxin-induced TLR-4 signaling. This effect could be partly due to the modulation of a hepatic enzyme that detoxifies LPS.

Relevant dose of the environmental contaminant, tributyltin, promotes histomorphological changes in the thyroid gland of male rats

Organotin compounds, such as tributyltin (TBT), are common environmental contaminants and suspected endocrine-disrupting chemicals. Tributyltin is found in antifouling paints, widely used in ships and other vessels. The present study evaluated whether a 15-day treatment with TBT at a dose of 100 ng/kg/day could induce histomorphological changes in the thyroid gland of rats. TBT promoted relevant alterations in the thyroid architecture, being the most relevant histological findings the presence of increased number of small-size follicles in the treated group. In qualitative analyses, colloid vacuolization, papillary budging structures, cystic degeneration and chronic thyroiditis, were observed. Moreover, histomorphometric analysis showed statistically significant changes in the follicular architecture of TBT-treated rats, mainly a decrease in the follicle area (colloid) and an increased epithelial height that resulted in an increased epithelial height/colloid ratio. Augmented collagen deposition was also seen in the thyroids of treated groups. In immunohistochemical (IHC) analyses, the localization of NIS protein was described and a significant increased proliferation index (evaluated by Ki67 positive cells) in the treated group was reported. As an indirect measurement of oxidative stress, mitochondrial protein SDHA was also analyzed by IHC analysis. Although the cytoplasmic expression of SDHA was observed in both groups, the staining intensity score was higher in TBT-treated group. Our results suggest that besides causing histomorphological changes, environmental relevant dose of TBT treatment can also induce oxidative alterations.

Tributyltin and triphenyltin induce 11β-hydroxysteroid dehydrogenase 2 expression and activity through activation of retinoid X receptor α

Exposure to the environmental pollutants organotins is of toxicological concern for the marine ecosystem and sensitive human populations, including pregnant women and their unborn children. Using a placenta cell model, we investigated whether organotins at nanomolar concentrations affect the expression and activity of 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2). 11β-HSD2 represents a placental barrier controlling access of maternal glucocorticoids to the fetus. The organotins tributyltin (TBT) and triphenyltin (TPT) induced 11β-HSD2 expression and activity in JEG-3 placenta cells, an effect confirmed at the mRNA level in primary human trophoblast cells. Inhibition/knock-down of retinoid X receptor alpha (RXRα) in JEG-3 cells reduced the effect of organotins on 11β-HSD2 activity, mRNA and protein levels, revealing involvement of RXRα. Experiments using RNA and protein synthesis inhibitors indicated that the effect of organotins on 11β-HSD2 expression was direct and caused by increased transcription. Induction of placental 11β-HSD2 activity by TBT, TPT and other endocrine disrupting chemicals acting as RXRα agonists may affect placental barrier function by altering the expression of glucocorticoid-dependent genes and resulting in decreased availability of active glucocorticoids for the fetus, disturbing development and increasing the risk for metabolic and cardiovascular complications in later life.

Disruptive effects of two organotin pesticides on the thyroid signaling pathway in Xenopus laevis during metamorphosis

Organotin compounds are the ubiquitous environmental pollutants due to their wide industrial and agricultural applications and unexpected releasing into the environment, which show characteristic of endocrine disruptors to interfere with the synthesis, receptor binding or action of endogenous-hormones. Organotin pesticides (OTPs) are used in agriculture and may impact endocrine functions on organisms. Thyroid hormones (THs) play fundamental roles in regulating the basal metabolism and energy balance, while thyroid function can be impaired by environmental contaminants. Therefore, it is crucial to clarify the effects and mechanisms of OTPs on hypothalamus-pituitary-thyroid (HPT) axis. In this study, Xenopus laevis tadpoles at stage 51 were exposed to fentin hydroxide and fenbutatin oxide (0.04, 0.20 and 1.00 μg·L^-1) for 21 days. It was found that both compounds caused inhibitory effects on metamorphic development of tadpoles (e.g., significant decrease in hindlimb length and retarding development). Triiodothyronine (T₃) significantly decreased in tadpoles exposed to 0.20 μg/L and 1.00 μg/L of the two OTPs for 14 days or 21 days. The expressions of TH responsive genes trβ, bteb and dio2 were down-regulated, while tshβ and slc5a5 were up-regulated. Surface plasmon resonance (SPR) binding assays showed that fentin hydroxide had a moderate affinity to recombinant human thyroid hormone receptor β but fenbutatin oxide did not have. Result of the SPR assay was highly consistent with the luciferase reporter gene assays that fentin hydroxide suppressed the relative luciferase activity in the presence of T₃ while fenbutatin oxide did not, demonstrating fentin hydroxide but not fenbutatin oxide displayed an antagonistic activity against T₃-TR complex mediated transcriptional activation. Overall, the findings elucidated the mechanisms induced by OTPs along HPT axis. These results highlighted the adverse influences of organotin pesticides on thyroid hormone- dependent development in vertebrates and the need for more comprehensive investigations of their potential ecological risks.

DNA fragmentation factor 40 expression in T cells confers sensibility to tributyltin-induced apoptosis

DNA fragmentation factor 40 (DFF40), an endonuclease, mediates the final and irreversible step of apoptosis by conducting oligonucleosomal DNA fragmentation. New emerging studies have proposed a role of DFF40 in genomic stability, besides its nuclease activity. Overexpression of DFF40 in tumoral cells increases their sensitivity to chemotherapeutic drugs. In this study, we sought to determine if DFF40 expression influences the toxicity of tributyltin (TBT), a well-known immunotoxic and apoptosis-inducing compound. The strategy used was to knockout DFF40 expression by CRISPR-cas9 method in Jurkat T cells and to determine the toxicity of TBT in DFF40 KO cells and DFF40 WT Jurkat cells. DFF40 KO Jurkat cells show an increase of cell viability following a 24-h TBT exposure (p < 0.05). There is a resistance to TBT-induced apoptosis determined by annexin V/PI am labeling (p < 0.05). Interestingly, the basal level of ROS rises in DFF40 KO Jurkat cells, but ROS production levels after TBT exposure remains at the same basal level. Other apoptosis or DNA damage makers (procaspase-3, caspase-6, and PARP cleavage) are significantly delayed and decreased. DFF40 deficient cells do not present histone H2AX phosphorylation, whereas wild-type cells present a phosphorylation following a 6-h exposure to TBT (p < 0.001). The re-expression of DFF40 in DFF40 KO cells restores the cytotoxic effects of TBT. Overall, these data suggest a role of DFF40 in cells sensitivity to TBT and possibly in DNA stability.

The tributyltin leads to obesogenic mammary gland abnormalities in adult female rats

Tributyltin chloride (TBT) is an obesogen associated with several complications. However, few investigations have evaluated TBT effects on adult mammary glands (MG). In this investigation, we assessed whether TBT's obesogenic effects resulted in abnormal MG fat pad expansion and other irregularities. TBT was administered to female rats (100 ng/kg/day for 15 days via gavage), and their MG morphophysiological development was assessed. We further assessed the MG fat pad for PPARγ, ERα, and aromatase protein expression, as well as inflammation, oxidative stress (OS), apoptosis and fibrosis. Irregular MG morphological development such as lower TEB number, alveolar (AB), lobule and differentiation (DF) score were observed in TBT rats. TBT rats had abnormal MG fat accumulation as evidenced by increased numbers of hypertrophic adipocytes, triglyceride (TG) levels and PPARγ expression. A strong negative correlation between the MG obesogenic makers and TEB number, AB and DF score were observed in TBT rats. MG inflammation was observed in TBT rats. A positive correlation between the MG obesogenic markers and inflammation were observed. High ERα and aromatase expression were observed in MG of TBT rats. MG OS, apoptosis and fibrosis were present in the TBT rats. Additionally, a positive correlation between the MG obesogenic markers and OS were observed in TBT rats. Thus, these data suggest that obesogenic TBT effects led to MG irregularities in the adult female rats.

The environmental contaminant tributyltin leads to abnormalities in different levels of the hypothalamus-pituitary-thyroid axis in female rats

Tributyltin is a biocide used in nautical paints, aiming to reduce fouling of barnacles in ships. Despite the fact that many effects of TBT on marine species are known, studies in mammals have been limited, especially those evaluating its effect on the function of the hypothalamus-pituitary-thyroid (HPT) axis. The aim of this study was to investigate the effects of subchronic exposure to TBT on the HPT axis in female rats. Female Wistar rats received vehicle, TBT 200 ng kg^-1 BW d^-1 or 1000 ng kg^-1 BW d^-1 orally by gavage for 40 d. Hypothalamus, pituitary, thyroid, liver and blood samples were collected. TBT200 and TBT1000 thyroids showed vacuolated follicular cells, with follicular hypertrophy and hyperplasia. An increase in epithelial height and a decrease in the thyroid follicle and colloid area were observed in TBT1000 rats. Moreover, an increase in the epithelium/colloid area ratio was observed in both TBT groups. Lower TRH mRNA expression was observed in the hypothalami of TBT200 and TBT1000 rats. An increase in Dio1 mRNA levels was observed in the hypothalamus and thyroid in TBT1000 rats only. TSH serum levels were increased in TBT200 rats. In TBT1000 rats, there was a decrease in total T4 serum levels compared to control rats, whereas T3 serum levels did not show significant alterations. We conclude that TBT exposure can promote critical abnormalities in the HPT axis, including changes in TRH mRNA expression and serum TSH and T4 levels, in addition to affecting thyroid morphology. These findings demonstrate that TBT disrupts the HPT axis. Additionally, the changes found in thyroid hormones suggest that TBT may interfere with the peripheral metabolism of these hormones, an idea corroborated by the observed changes in Dio1 mRNA levels. Therefore, TBT exposition might interfere not only with the thyroid axis but also with thyroid hormone metabolism.

The obesogen tributyltin induces features of polycystic ovary syndrome (PCOS): a review

Polycystic ovary syndrome (PCOS) is a heterogeneous syndrome characterized by abnormal reproductive cycles, irregular ovulation, and hyperandrogenism. This complex disorder has its origins both within and outside the hypothalamic-pituitary-ovarian axis. Cardio-metabolic factors, such as obesity and insulin resistance, contribute to the manifestation of the PCOS phenotype. Polycystic ovary syndrome is one of the most common endocrine disorders among women of reproductive age. Growing evidence suggested an association between reproductive and metabolic features of PCOS and exposure to endocrine-disrupting chemicals (EDC), such as bisphenol A. Further, the environmental obesogen tributyltin (TBT) was shown to induce reproductive, metabolic and cardiovascular abnormalities resembling those found in women and animal models of PCOS. However, the causal link between TBT exposure and PCOS development remains unclear. The objective of this review was to summarize the most recent research findings on the potential association between TBT exposure and development of PCOS-like features in animal models and humans.

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.

Protective effects of fucoxanthin and fucoxanthinol against tributyltin-induced oxidative stress in HepG2 cells

Tributyltin (TBT) is a biocide extremely toxic to a wide range of organisms, which has been used for decades for industrial purposes. Fucoxanthin is a natural carotenoid that is isolated from seaweed, and fucoxanthinol is a major primary metabolite of fucoxanthin. Although fucoxanthin and fucoxanthinol have been reported to possess anti-oxidant activities in vitro, little is known as to whether they protect against TBT-induced oxidative stress in cultured cells. In the present study, the protective effect of fucoxanthin and fucoxanthinol against oxidative stress induced by TBT was investigated. The data showed that incubation of HepG2 cells with 0.2 μM TBT significantly increased cell apoptosis, whereas treatment with fucoxanthin or fucoxanthinol (3 μM) significantly recovered cell viability. In addition, fucoxanthinol treatment significantly decreased the intracellular reactive oxygen species (ROS) and malondialdehyde (MDA) in HepG2 cells incubated with TBT. Moreover, fucoxanthin and fucoxanthinol markedly increased the expression level of Bcl-2/Bax. These results demonstrated that both fucoxanthin and fucoxanthinol effectively prevented cytotoxicity in HepG2 cells treated with TBT, and the protective effect was likely associated with decreased intracellular ROS and MDA and increased Bcl-2/Bax levels.

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 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.

Tributyltin chloride disrupts aortic vascular reactivity and increases reactive oxygen species production in female rats

Organotin compounds, such as tributyltin (TBT), are environment contaminants that induce bioaccumulation and have potential toxic effects on marine species and mammals. TBT have been banned by the International Maritime Organization in 2003. However, the assessment of butyltin and metal contents in marine sediments has demonstrated high residual levels of TBT in some cases exceeding 7000 ng Sn g^-1. The acceptable daily intake (ADI) level for TBT established by the World Health Organization is 0.5 μg/kg bw/day is based on genotoxicity, reproduction, teratogenicity, immunotoxicity, and mainly neurotoxicity. However, their effect on the cardiovascular system is not well understood. In this study, female rats were exposed to 0.5 μg/kg/day of TBT for 15 days with the goal of understanding the effect of TBT on vascular function. Female Wistar rats were treated daily by gavage and divided into control (n = 10) and TBT (n = 10) groups. The aortic rings were incubated with phenylephrine in both the presence and absence of endothelium. The phenylephrine concentration-response curves were generated by exposing endothelium-intact samples to N^G-nitro-L-arginine methyl ester (L-NAME), apocynin, superoxide dismutase (SOD), catalase, tiron, and allopurinol. Acetylcholine (ACh) and sodium nitroprusside (SNP) were used to evaluate the relaxation response. Exposure to TBT reduced serum 17β-estradiol E₂ levels and increased vascular reactivity. After incubation with L-NAME, the vascular reactivity to phenylephrine was significantly higher. Apocynin, SOD, catalase, and tiron decreased the vascular reactivity to phenylephrine to a significantly greater extent in TBT-treated rats than in the control rat. The relaxation induced by ACh and SNP was significantly reduced in TBT rats. Exposure to TBT induced aortic wall atrophy and increased superoxide anion production and collagen deposition. These results provide evidence that exposing rats to the current ADI for TBT (0.5 μg/kg) for 15 days induced vascular dysfunction due to oxidative stress and morphological damage and should be considered an important cardiovascular risk factor.

The Pollutant Organotins Leads to Respiratory Disease by Inflammation: A Mini-Review

Organotins (OTs) are organometallic pollutants. The OTs are organometallic pollutants that are used in many industrial, agricultural, and domestic products, and it works as powerful biocidal compound against large types of microorganisms such as fungi and bacteria. In addition, OTs are well known to be endocrine-disrupting chemicals, leading abnormalities an "imposex" phenomenon in the female mollusks. There are some studies showing that OTs' exposure is responsible for neural, endocrine, and reproductive dysfunctions in vitro and in vivo models. However, OTs' effects over the mammalian immune system are poorly understood, particularly in respiratory diseases. The immune system, as well as their cellular components, performs a pivotal role in the control of the several physiologic functions, and in the maintenance and recovery of homeostasis. Thus, it is becoming important to better understand the association between environmental contaminants, as OTs, and the physiological function of immune system. There are no many scientific works studying the relationship between OTs and respiratory disease, especially about immune system activation. Herein, we reported studies in animal, humans, and in vitro models. We searched studies in PUBMED, LILACS, and Scielo platforms. Studies have reported that OTs exposure was able to suppress T helper 1 (Th1) and exacerbate T helper 2 (Th2) response in the immune system. In addition, OTs' contact could elevate in the airway inflammatory response, throughout a mechanism associated with the apoptosis of T-regulatory cells and increased oxidative stress response. In addition, OTs induce macrophage recruitment to the tissue, leading to the increased necrosis, which stimulates an inflammatory cytokines secretion exacerbating the local inflammation and tissue function loss. Thus, the main intention of this mini-review is to up to date the main findings involving the inflammatory profile (especially Th1 and Th2 response) in the respiratory tract as a result of OTs' exposure.