Elsevier

Toxicology Letters

Volume 235, Issue 1, 19 May 2015, Pages 45-59
Toxicology Letters

Tributyltin chloride leads to adiposity and impairs metabolic functions in the rat liver and pancreas

https://doi.org/10.1016/j.toxlet.2015.03.009Get rights and content

Highlights

  • Tributyltin chloride modulates adipose tissue-specific in female rats.

  • Tributyltin chloride up-regulated ER-alpha expression in vivo.

  • Tributyltin chloride down-regulated ER-alpha expression in 3T3-L1 cells.

  • Tributyltin chloride impairs liver and pancreas morphophysiology.

Abstract

Tributyltin chloride (TBT) is an environmental contaminant used in antifouling paints of boats. Endocrine disruptor effects of TBT are well established in animal models. However, the adverse effects on metabolism are less well understood. The toxicity of TBT in the white adipose tissue (WAT), liver and pancreas of female rats were assessed. Animals were divided into control and TBT (0.1 μg/kg/day) groups. TBT induced an increase in the body weight of the rats by the 15th day of oral exposure. The weight gain was associated with high parametrial (PR) and retroperitoneal (RP) WAT weights. TBT-treatment increased the adiposity, inflammation and expression of ERα and PPARγ proteins in both RP and PR WAT. In 3T3-L1 cells, estrogen treatment reduced lipid droplets accumulation, however increased the ERα protein expression. In contrast, TBT-treatment increased the lipid accumulation and reduced the ERα expression. WAT metabolic changes led to hepatic inflammation, lipid accumulation, increase of PPARγ and reduction of ERα protein expression. Accordingly, there were increases in the glucose tolerance and insulin sensitivity tests with increases in the number of pancreatic islets and insulin levels. These findings suggest that TBT leads to adiposity in WAT specifically, impairing the metabolic functions of the liver and pancreas.

Graphical abstract

Diagram of the tissue–tissue cross-talk in tributyltin chloride (TBT) and metabolic homeostasis. TBT derived from exogenous sources stimulates (green line) or inhibits (red line) transcription from metabolic genes (tissue-specific). TBT stimulates PPARγ and inhibits ERα protein expression followed with hepatic inflammation and lipid storage. Interestingly, TBT stimulates both PPARγ and ERα protein expression in adipose tissue associated with inflammation and adiposity. Additionally, liver and adipose tissue-derived impairments modulated glucose tolerance (GTT) and insulin sensivity (IST) tests.

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Introduction

Organotin chemicals (OTs) are a diverse class of widely distributed xenobiotics (Fent, 1996, Graceli et al., 2013). These organometallic pollutants are used as biocides in antifouling paints (Barnes and Stoner, 1959, Grün and Blumberg, 2006), although use for this purpose has been restricted in recent years, on the basis of their various toxic effects (IMO, 2001, Oberdõrster and McClellan-Green, 2002, Graceli et al., 2013). OTs are markedly toxic to oysters and other non-target molluscs and are considered to be endocrine-active environmental chemicals. For instance, the tributyltin chloride (TBT) is inducers of imposex, the imposition of male sex characteristics on female snails (Fent, 1996, Oberdõrster and McClellan-Green, 2002). The mechanism by which TBT cause imposex is unclear, but TBT-induced inhibition of an aromatase, a cytochrome-P450 that converts testosterone into estrogen, seems to be involved (Oberdõrster and McClellan-Green, 2002).

Several investigations have shown that exposure to OTs cause hepatic, neural, immune and reproductive toxicity (Wiebkin et al., 1982, Kletzien et al., 1992, Tafuri, 1996, Grote et al., 2006, Grondin et al., 2007) in various mammalian experimental models by accumulation of TBT and their metabolites, as dibutyltin (DBT) and inorganic tin (iSn) (Krajnc et al., 1984, Dorneles et al., 2008). The iSn is poorly absorbed by the gastro-intestinal tract (GIT) and is associated with OTs metabolization into iSn by mammals (Appel, 2004). It has been suggested that an important fraction of iSn may be present in the bodies of mammals, as a result of OT contamination, which strengthens the importance of the total tin determination for evaluating the exposure of mammalian to OTs (Appel, 2004, Dorneles et al., 2008).

Among other effects, reports on their toxicity indicate that TBT promote adipogenesis in vivo, in vitro and in utero (Grün et al., 2006, Kirchner et al., 2010, Penza et al., 2011). Furthermore, TBT alters the stem cell compartment by sensitising multipotent stromal stem cells to differentiate into adipocytes, similar to the actions of the obesogen class of environmental chemicals (Grün and Blumberg, 2006, Kirchner et al., 2010).

Obesogens can be functionally defined as chemicals that inappropriately alter lipid homeostasis and fat storage, metabolic set points, energy balance, or the regulation of appetite and satiety to promote fat accumulation and obesity (Grün et al., 2006, Grün and Blumberg, 2007). The obesity and metabolic disorders related in the developed world are not associated only to overeating or inactivity, although these are clear factors (Newbold et al., 2009). Previous studies supported that a role of environmental factors in the development of obesity, such as environmental obesogens (Grün et al., 2006, Newbold et al., 2009). The rise in obesity coincides with an exponential increase in the use of industrial chemicals over the last 40 years. Numerous xenobiotics have attracted attention for their potential contribution to the increased obesity rate (Heindel and vom Saal, 2009, de Cock and van de Bor, 2014).

The white adipose tissue (WAT) is the principal modulator of metabolic function in mammals. WAT plays a pivotal role in regulating the cascade of paracrine events necessary for energetic metabolism, immune process and reproductive function (Guerre-Millo, 2002, Kershaw and Flier, 2004, Badman and Flier, 2005, MacLaren et al., 2008, Monget et al., 2008). In females, the granulosa cells in ovary secrete estrogen (E2), which acts a important modulation in the typical distribution of body fat and WAT metabolism, mediated by two nuclear estrogen receptors (ERs), ER alpha (ERα) and beta (ERβ) (Danilovich et al., 2000). The enlarged fat mass deposition that occurs in women as they enter menopause and the growth of fat mass reported in various rodent models of E2 deficiency represent the clearest physiological examples of the anti-adipogenic action of E2 (Danilovich et al., 2000, Heine et al., 2000). E2 modulates WAT increasing lipolysis through control of the expression of genes that regulate lipogenesis, adipocyte differentiation and metabolism (Cooke and Naaz, 2004, Pallottini et al., 2008).

Despite these discoveries of TBT and E2 actions in WAT, few studies have explored the effect of TBT signaling directly in ERs on mammalian metabolic function (Grün and Blumberg, 2006, Penza et al., 2011). Consequently, herein, the aim of this study was to determine the association of TBT-induced adverse effects on the parametrial and retroperitoneal WAT (in vivo), 3T3-L1 cells (in vitro) and the metabolic functions of the liver and pancreas associated with the impairment of the E2 levels in female rats.

Section snippets

Experimental animals and treatments

Adult female Wistar rats weighing approximately 230 g (12 week old) were housed in polypropylene cages under controlled temperature and humidity conditions with a 12-h light/dark cycle and free access to water and food. The rats were divided into two groups: (1) The tributyltin chloride group (TBT, n = 10), treated daily with tributyltin chloride (0.1 μg/kg/day of TBT diluted in vehicle consisting of 0.4% ethanol; Sigma, St. Louis, MO) for 15 day by oral administration (Lang Podratz et al., 2012);

Effect of TBT on body weight and total body fat

To determine the importance of TBT exposure in the regulation of WAT homeostasis, we monitored the body weights of the TBT-treated rats for 15 days and found that there was a significant increase by the 15th day of treatment (n = 10, p  0.05, Fig. 1A). Consistent with the growth curves, the TBT group had increased visceral adiposity as reflected by increases in the weights (fat mass/body weight) of both the parametrial and retroperitoneal fat pads (n = 10, p  0.05, Fig. 1B). The food intake and the

Discussion

In the present study, we showed that TBT was able to induce changes in the morphophysiology of female rat WAT, as well as pancreas and liver tissues. These effects were related to changes in adiposity and estrogen levels. The WAT remodelling included increases in the adipocyte size, decreases in the adipocyte number and changes in the numbers of mast cells, along with modulation of the protein expression of ERα and PPARγ in the WAT. Additionally, the exposure to TBT increased the quantity of

Conflict of interest

The authors declare that there are no conflicts of interest related to this work.

Acknowledgments

This research supported by Ciências Sem Fronteiras-CAPES (#18196-12-8), FAPES (#45446121/2009-002) and UFES (#PIVIC 2010-11).

References (95)

  • K. Grote et al.

    Effects of peripubertal exposure to triphenyltin on female sexual development of the rat

    Toxicology

    (2006)
  • J.J. Heindel et al.

    Role of nutrition and environmental endocrine disrupting chemicals during the perinatal period on the aetiology of obesity

    Mol. Cell Endocrinol.

    (2009)
  • H. Homma et al.

    Estrogen suppresses transcription of lipoprotein lipase gene Existence of a unique estrogen response element on the lipoprotein lipase promoter

    J. Biol. Chem.

    (2000)
  • E.I. Krajnc et al.

    Toxicity of bis(tri-n-butyltin) oxide in the rat. I. Short-term effects on general parameters and on the endocrine and lymphoid systems

    Toxicol. Appl. Pharmacol.

    (1984)
  • C.C. Lee et al.

    Organotin contamination in fishes with different living patterns and its implications for human health risk in Taiwan

    Environ. Pollut.

    (2005)
  • A. Ludgero-Correia et al.

    Effects of high-fat diet on plasma lipids, adiposity, and inflammatory markers in ovariectomized C57BL/6 mice

    Nutrition

    (2012)
  • P. Monget et al.

    Adipose tissue, nutrition and reproduction: what is the link?

    Bull. Acad. Natl. Med.

    (2008)
  • Y.M. Mu et al.

    Combined treatment with specific ligands for PPARgamma:RXR nuclear receptor system markedly inhibits the expression of cytochrome P450arom in human granulosa cancer cells

    Mol. Cell Endocrinol.

    (2001)
  • Y.M. Mu et al.

    Insulin sensitizer, troglitazone, directly inhibits aromatase activity in human ovarian granulosa cells

    Biochem. Biophys. Res. Commun.

    (2000)
  • Y. Murata et al.

    Effect of estrogen deficiency in the male: the ArKO mouse model

    Mol. Cell Endocrinol.

    (2002)
  • R.R. Newbold et al.

    Environmental estrogens and obesity

    Mol. Cell Endocrinol.

    (2009)
  • E. Oberdõrster et al.

    Mechanisms of imposex induction in the mud snail Ilyanassa obsoleta: TBT as a neurotoxin and aromatase inhibitor

    Mar. Environ. Res.

    (2002)
  • M. Penza et al.

    The environmental chemical tributyltin chloride (TBT) shows both estrogenic and adipogenic activities in mice which might depend on the exposure dose

    Toxicol. Appl. Pharmacol.

    (2011)
  • S.M. Rodrigues et al.

    Tributyltin contributes in reducing the vascular reactivity to phenylephrine in isolated aortic rings from female rats

    Toxicol. Lett.

    (2014)
  • M. Saitoh et al.

    Tributyltin or triphenyltin inhibits aromatase activity in the human granulosa-like tumor cell line KGN

    Biochem. Biophys. Res. Commun.

    (2001)
  • S. Sharan et al.

    Effects of low dose treatment of tributyltin on the regulation of estrogen receptor functions in MCF-7 cells

    Toxicol. Appl. Pharmacol.

    (2013)
  • H. Shi et al.

    Sexual differences in the control of energy homeostasis

    Front Neuroendocrinol.

    (2009)
  • P. Tontonoz et al.

    Stimulation of adipogenesis in fibroblasts by PPAR gamma 2, a lipid-activated transcription factor

    Cell

    (1994)
  • X. Wang et al.

    Signal cross-talk between estrogen receptor alpha and beta and the peroxisome proliferator-activated receptor gamma1 in MDA-MB-231 and MCF-7 breast cancer cells

    Mol. Cell Endocrinol.

    (2002)
  • P. Wiebkin et al.

    The metabolism and toxicity of some organotin compounds in isolated rat hepatocytes

    Toxicol. Appl. Pharmacol.

    (1982)
  • N. Yamabe et al.

    Beneficial effect of 17b-estradiol on hyperglycemia and islet b-cell functions in a streptozotocin-induced diabetic rat model

    Toxicol. Appl. Pharmacol.

    (2010)
  • M. Yepuru et al.

    Estrogen receptor-β-selective ligands alleviate high-fat diet and ovariectomy-induced obesity in mice

    J. Biol. Chem.

    (2010)
  • R.S. Ahima

    Adipose tissue as an endocrine organ

    Obesity (Silver Spring)

    (2006)
  • P. Alonso-Magdalena et al.

    The estrogenic effect of bisphenol A disrupts pancreatic beta-cell function in vivo and induces insulin resistance

    Environ. Health Perspect.

    (2006)
  • A. Anwar et al.

    Site-specific regulation of oestrogen receptor-alpha and -beta by oestradiol in human adipose tissue

    Diabetes Obes.

    (2001)
  • K.E. Appel

    Organotin compounds: toxicokinetic aspects

    Drug Metab. Rev.

    (2004)
  • M.K. Badman et al.

    The gut and energy balance: visceral allies in the obesity wars

    Science

    (2005)
  • L.S. Baptista et al.

    Adipose tissue of control and ex-obese patients exhibit differences in blood vessel content and resident mesenchymal stem cell population

    Obes. Surg.

    (2009)
  • J.M. Barnes et al.

    The toxicology of tin compounds

    Pharmacol. Rev.

    (1959)
  • V. Bieghs et al.

    Internalization of modified lipids by CD36 and SR-A leads to hepatic inflammation and lysosomal cholesterol storage in Kupffer cells

    PLoS One

    (2012)
  • G. Bryzgalova et al.

    Evidence that oestrogen receptor-alpha plays an important role in the regulation of glucose homeostasis in mice: insulin sensitivity in the liver

    Diabetologia

    (2006)
  • G. Bryzgalova et al.

    Mechanisms of antidiabetogenic and body weightlowering effects of estrogen in high-fat diet-fed mice

    Am. J. Physiol. Endocrinol.

    (2008)
  • R. Chamorro-García et al.

    Transgenerational inheritance of increased fat depot size, stem cell reprogramming, and hepatic steatosis elicited by prenatal exposure to the obesogen tributyltin in mice

    Environ. Health Perspect.

    (2013)
  • P.S. Cooke et al.

    Role of estrogens in adipocyte development and function

    Exp. Biol. Med. (Maywood)

    (2004)
  • J.F. Couse et al.

    Tissue distribution and quantitative analysis of estrogen receptor-alpha (ERalpha) and estrogen receptor-beta (ERbeta) messenger ribonucleic acid in the wild-type and ERalpha-knockout mouse

    Endocrinology

    (1997)
  • N. Danilovich et al.

    Estrogen deficiency, obesity, and skeletal abnormalities in follicle-stimulating hormone receptor knockout (FORKO) female mice

    Endocrinology

    (2000)
  • Z. Dang et al.

    The balance between concurrent activation of ERs and PPARs determines daidzein-induced osteogenesis and adipogenesis

    J. Bone Miner Res.

    (2004)
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