Organotin compounds

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.

Pharmacological evaluation of the mechanisms involved in increased adiposity in zebrafish triggered by the environmental contaminant tributyltin

One proposed contributing factor to the rise in overweight and obesity is exposure to endocrine disrupting chemicals. Tributyltin chloride (TBT), an organotin, induces adipogenesis in cell culture models and may increases adipose mass in vivo in vertebrate model organisms. It has been hypothesized that TBT acts via the peroxisome proliferator activated receptor (PPAR)γ-dependent pathway. However, the mechanisms involved in the effects of TBT exposure on in vivo adipose tissue metabolism remain unexplored. Semitransparent zebrafish larvae, with their well-developed white adipose tissue, offer a unique opportunity for studying the effects of toxicant chemicals and pharmaceuticals on adipocyte biology and whole-organism adiposity in a vertebrate model. Within hours, zebrafish larvae, treated at environmentally-relevant nanomolar concentrations of TBT, exhibited a remarkable increase in adiposity linked to adipocyte hypertrophy. Under the experimental conditions used, we also demonstrated that zebrafish larvae adipose tissue proved to be highly responsive to selected human nuclear receptor agonists and antagonists. Retinoid X receptor (RXR) homodimers and RXR/liver X receptor heterodimers were suggested to be in vivo effectors of the obesogenic effect of TBT on zebrafish white adipose tissue. RXR/PPARγ heterodimers may be recruited to modulate adiposity in zebrafish but were not a necessary requirement for the short term in vivo TBT obesogenic effect. Together, the present results suggest that TBT may induce the promotion of triacylglycerol storage in adipocytes via RXR-dependent pathways without necessary using PPAR isoforms.

Deleterious effects of prepubertal corticosterone treatment on rat prostate

PURPOSE

To investigate the structural and functional changes induced by corticosterone (CORT) in the ventral prostrate (VP) of rats in order to study chronic stress effects in the prepubertal phase.

METHODS

Wistar rats received daily saline or CORT injections during the pubertal period from the 5th to 25th day of postnatal life. The animals were distributed into four groups: 1 - Control (n=5); 2 - Control 99mTc-P (n=5); 3 - Treated with CORT (n=14); 4 - Treated with CORT and 99mTc-P (n=10). All rats were sacrificed at two months of age. Technical tissue uptakes of 99mTc-P were used to evaluate the functional and stereological methods for morphological analysis.

RESULTS

Acini distribution in the group treated with CORT differed significantly (p<0.0001) from the control. The control group's epithelial average height (10.01±0.24 microns) was statistically significant (p<0.0001) from rats treated with CORT (19.27±0.73microns). The collagen distribution was lower in the treated group (2.79%) when compared to control (3.97%). The radioactivity percentage in the groups marked with 99mTc-P (%Ati/g) did not demonstrate a statistically significant difference (p=0.285897).

CONCLUSION

Chronic administration of corticosterone in prepubertal rats causes changes in their acinar structure and their ventral prostate stroma, indicating possible deleterious effects of this hormone.

Some laboratory blood indicators in tractor drivers exposed to pesticides

Pesticides represent group of extremely different compounds or mixed compounds. They are produced in the form of powder for direct application, powder for suspension, concentrated suspension, concentration of emulsion, and in other forms as well. Influence of pesticides to exposed workers mainly depends on technology of pesticide application use. All poisons, just like pesticides that come in organism in some way and reach the location of their metabolism, accumulation in the body or extraction must get there through blood. Pesticides influence stem cells in bone marrow, then maturation process of blood elements and can damage mature blood cells in blood circulation. The sample encompassed 142 tractor drivers employed in state agricultural unions who were exposed to pesticides during their work. Concerning annual and daily exposure to pesticides in examined persons is determined that daily extent ranged from 3 to 12 hours and annual from 5 to 125 days, 60.93 in average. In the paper are analyzed following blood count parameters: erythrocytes, hemoglobin, leucocytes and thrombocytes The aim of the paper is to investigate whether pesticides influence changed blood count of tractor drivers exposed to pesticides during their work. Analysis of obtained results indicates that exposure to pesticides, like in examined group of workers, has not influenced damage in any of investigated blood count parameter.

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.

Reduction of spermatogenesis and steroidogenesis in mice after fentin and fenbutatin administration

The present study was designed to assess potential reproductive toxicity caused by fentin and fenbutatin in the mice. Adult male mice received i.p. injections of fentin hydroxide and fenbutatin oxide at a dose of 0, 10 or 25 microg/kg body weight on 1st, 3rd and 5th day of experimentation. Mice were sacrificed on day 25 and analyzed for spermatogenesis and steroidogenesis. A significant decrease in epididymal sperm count, sperm motility, sperm viability and sperm function (HOS coiling) were observed in experimental mice when compared with controls. The decrease in sperm quantity and quality was significant in the 25 microg/kg group than that in the control group. The activity levels of testicular steroidogenic enzymes, 3beta-hydroxysteroid dehydrogenase (3beta-HSD) and 17beta-hydroxysteroid dehydrogenase (17beta-HSD) were significantly decreased in treated mice indicating decreased steroidogenesis after organotin compounds administration. The levels of serum testosterone decreased with an increase in follicle stimulating hormone and luteinizing hormone in experimental mice when compared to control mice. The results suggest that fentin and fenbutatin cause impairment of spermatogenesis through the inhibition of testosterone production.

Steroid levels in crinoid echinoderms are altered by exposure to model endocrine disruptors

Sexual steroids (testosterone and estradiol) were measured in the whole body of wild specimens of the crinoid Antedon mediterranea collected from the Tyrrhenian Sea (Italy). Testosterone levels (274-1,488 pg/g wet weight (w.w.)) were higher than those of estradiol (60-442 pg/g w.w.) and no significant differences between males and females were observed. No clear seasonal trend was either detected - individuals from February, June and October 2004 analyzed - apart from a peak of estradiol in males in autumn. Nonetheless, dramatic changes on tissue steroid levels were observed when individuals were exposed to model androgenic and anti-androgenic compounds for 2 and 4 weeks. The selected compounds were 17 alpha-methyltestosterone (17 alpha-MT), triphenyltin (TPT), fenarimol (FEN), cyproterone acetate (CPA), and p,p'-DDE. Endogenous testosterone levels were significantly increased after exposure to 17 alpha-MT, TPT and FEN, while different responses were observed for estradiol; 17 alpha-MT and FEN increased endogenous estradiol (up to seven-fold), and TPT lead to a significant decrease. Concerning the anti-androgenic compounds, CPA significantly reduced testosterone in a dose-dependent manner without altering estradiol levels, whereas specimens exposed to p,p'-DDE at a low dose (24 ng/L) for 4 weeks showed a four-fold increase in T levels. Overall, the data show the ability of the selected compounds to alter endogenous steroid concentrations in A. mediterranea, and suggest the existence in this echinoderm species of vertebrate-like mechanisms that can be affected by exposure to androgenic and anti-androgenic chemicals.

Organotins disrupt the 11beta-hydroxysteroid dehydrogenase type 2-dependent local inactivation of glucocorticoids

Organotins, important environmental pollutants widely used in agricultural and industrial applications, accumulate in the food chain and induce imposex in several marine species as well as neurotoxic and immunotoxic effects in higher animals. Reduced birth weight and thymus involution, observed upon exposure to organotins, can also be caused by excessive glucocorticoid levels. We now demonstrate that organotins efficiently inhibit 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2), converting active 11beta-hydroxyglucocorticoids into inactive 11-ketoglucocorticoids, but not 11beta-HSD1, which catalyzes the reverse reaction. Di- and tributyltin as well as di- and triphenyltin inhibited recombinant and endogenous 11beta-HSD2 in lysates and intact cells with IC50 values between 500 nM and 3 microM. Dithiothreitol protected 11beta-HSD2 from organotin-dependent inhibition, indicating that organotins act by binding to one or more cysteines. Mutational analysis and 3-D structural modeling revealed several important interactions of cysteines in 11beta-HSD2. Cys90, Cys228, and Cys264 were essential for enzymatic stability and catalytic activity, suggesting that disruption of such interactions by organotins leads to inhibition of 11beta-HSD2. Enhanced glucocorticoid concentrations due to disruption of 11beta-HSD2 function may contribute to the observed organotin-dependent toxicity in some glucocorticoid-sensitive tissues such as thymus and placenta.

Toxic Encephalopathies

Effective brain function is dependent on precise and complex interactions among neurotransmitters, hormones, enzymes, and electrolytes. Many of the chemically complex substances with which we come into contact can disrupt this intricately balanced system. Toxic substances, whether ingested, inhaled, or absorbed through the skin, may cause an encephalopathic state directly by affecting the brain itself or indirectly by compromising the brain's supportive systems. The article focuses on neurotoxins (heavy metals, solvents and vapors, pesticides, and natural neurotoxins) that directly induce an encephalopathic state.

Regenerative response and endocrine disrupters in crinoid echinoderms: an old experimental model, a new ecotoxicological test

The regenerative phenomena that reproduce developmental processes in adult organisms and are regulated by endocrine and neurohumoral mechanisms can provide new sensitive tests for monitoring the effects of exposure to anthropogenic chemicals such as endocrine disrupter (ED) contaminants. These pollutants in fact can be bioaccumulated by the organisms, causing dysfunctions in steroid hormone production/metabolism and activities and inducing dramatic effects on reproductive competence, development and growth in many animals, man included. Current research is exploring the effects of exposure to different classes of compounds well known for their ED activity, such as polychlorinated biphenyls (PCBs), nonylphenols and organotins, on regenerative potential of echinoderms, a relatively unexplored and promising applied approach which offers the unique chance to study physiological developmental processes in adult animals. The selected test species is the crinoid Antedon mediterranea, which represents a valuable experimental model for investigation into the regenerative process from the macroscopic to the molecular level. The present study employs an integrated approach which combines exposure experiments, chemical analysis and biological analysis utilizing classical methods of light (LM) and electron (TEM and SEM) microscopy and immunocytochemistry. The experiments were carried out on experimentally induced arm regenerations in controlled conditions with exposure concentrations comparable to those of moderately polluted coastal zones in order to reproduce common conditions of exposure to environmental contaminants. The results of the exposure tests were analysed in terms of effects at the whole organism, at the tissue and cellular level, and possible sites of action of EDs. Our results show that prolonged exposure to these compounds significantly affects the regenerative mechanisms by inducing appreciable anomalies in terms of regeneration times, overall growth, general morphology and histological and cellular pattern. A concentration/effect relationship could be found for all substances. Interestingly, contrasting results in terms of inhibition or acceleration of regeneration phenomenon were obtained for different chemicals.

Spermatogenetic Disorders in Adult Rats Exposed to Tributyltin Chloride during Puberty

Adverse effects of tributyltin (TBT) chloride were investigated on the reproductive system in male adult rats as exposed during puberty. Fifty Sprague-Dawley rats at the age of 35 days were assigned to five different groups: negative control receiving vehicle, methyltestosterone (10 mg/kg B.W.), and TBT chloride treatments (5, 10, and 20 mg/kg B.W.). Animals were treated by oral gavage for ten consecutive days and sacrificed at 5 weeks after final treatment. The treatment of TBT chloride at the high dose of 20 mg/kg B.W. significantly decreased homogenization-resistant testicular sperm counts (p<0.05). The TBT chloride treatment at the doses of 10 and 20 mg/kg B.W. also significantly decreased caudal epididymal sperm counts (p<0.01). Some of motion kinematic parameters (motility, mean angular displacement, lateral head displacement, and dance) of sperms retrieved from vasa deference were significantly decreased in rats treated with the TBT chloride at the dose of 20 mg/kg B.W. (p<0.05). These results provide a further evidence that an exposure to TBT chloride during pubertal period in male rats produces spermatogenic disorders characterized by decreasing testicular and epididymal sperm counts and some motion parameters of sperms in the vasa deference.

Pre-implantation embryonic loss induced by tributyltin chloride in rats

The effect of tributyltin chloride (TBTCl) administered during early pregnancy on pregnancy maintenance was evaluated in rats. Inseminated females were orally administered TBTCl at a dose of 0, 8.1, 12.2 or 16.3 mg/kg on day 0 through day 7 of pregnancy. Females were sacrificed on day 20 of pregnancy and pregnancy outcome was determined. Pregnancy failure, which was evidenced by absence of implantation sites, was found in 0 of the 10, in 2 of the 11, in 10 of the 14 and in 10 of the 13 females at 0, 8.1, 12.2 and 16.3 mg/kg, respectively. The rate of pregnancy failure was significantly higher in the 12.2 and 16.3 mg/kg groups than that in the control group. In females with successful pregnancy, the numbers of corpora lutea, implantations and post-implantation loss per litter were comparable across all groups. No increase in the incidence of malformed fetuses was found in any TBTCl-treated groups. Thus it appears that TBTCl causes pregnancy failure after administration during very early pregnancy.