The Cerebellum

, Volume 11, Issue 2, pp 575–586 | Cite as

Maternal Thimerosal Exposure Results in Aberrant Cerebellar Oxidative Stress, Thyroid Hormone Metabolism, and Motor Behavior in Rat Pups; Sex- and Strain-Dependent Effects

  • Z. L. Sulkowski
  • T. Chen
  • S. Midha
  • A. M. Zavacki
  • Elizabeth M. Sajdel-Sulkowska
Original Paper

Abstract

Methylmercury (Met-Hg) and ethylmercury (Et-Hg) are powerful toxicants with a range of harmful neurological effects in humans and animals. While Met-Hg is a recognized trigger of oxidative stress and an endocrine disruptor impacting neurodevelopment, the developmental neurotoxicity of Et-Hg, a metabolite of thimerosal (TM), has not been explored. We hypothesized that TM exposure during the perinatal period impairs central nervous system development, and specifically the cerebellum, by the mechanism involving oxidative stress. To test this, spontaneously hypertensive rats (SHR) or Sprague–Dawley (SD) rat dams were exposed to TM (200 μg/kg body weight) during pregnancy (G10–G15) and lactation (P5–P10). Male and female neonates were evaluated for auditory and motor function; cerebella were analyzed for oxidative stress and thyroid metabolism. TM exposure resulted in a delayed startle response in SD neonates and decreased motor learning in SHR male (22.6%), in SD male (29.8%), and in SD female (55.0%) neonates. TM exposure also resulted in a significant increase in cerebellar levels of the oxidative stress marker 3-nitrotyrosine in SHR female (35.1%) and SD male (14.0%) neonates. The activity of cerebellar type 2 deiodinase, responsible for local intra-brain conversion of thyroxine to the active hormone, 3′,3,5-triiodothyronine (T3), was significantly decreased in TM-exposed SHR male (60.9%) pups. This coincided with an increased (47.0%) expression of a gene negatively regulated by T3, Odf4 suggesting local intracerebellar T3 deficiency. Our data thus demonstrate a negative neurodevelopmental impact of perinatal TM exposure which appears to be both strain- and sex-dependent.

Keywords

Ethylmercury Rat Cerebellum Oxidative stress marker 3-nitrotrosine (3-NT) Type 2 deiodinase (D2) 

Notes

Acknowledgments

We would like to thank the Mercury as a Global Hazard SGIG for the grant awarded by the College of William and Mary to Z.L. Sulkowski, the Autism Research Institute and SafeMinds for grants awarded to Dr. Sajdel-Sulkowska, and the NIDDK-DK76117 grant awarded to A.M. Zavacki. We would also like to thank Puja Parekh of the College of William for participating in the initial experiments and Ming Xu, Dept. Integrative Physiology, Gunma University Graduate School of Medicine, Maebashi Gunma, Japan, for initial tissue analysis. We also acknowledge the following Sponsored Research Staff members at Brigham and Women’s Hospital: Amrutha E. Mathew, Pooja Mathew and Ashesh Shresta for RNA preparation, and Dr. Alaptagin Khan for PCR primer validation.

References

  1. 1.
    Bokara KK, Brown E, McCormick R, Yallapragada PR, Rajanna S, Bettaiya R. Lead-induced increase in antioxidant enzymes and lipid peroxidation products in developing rat brain. Biometals. 2008;21:9–16.PubMedCrossRefGoogle Scholar
  2. 2.
    Windham GC, Zhang L, Gunier R, Croen LA, Grether JK. Autism spectrum disorders in relation to distribution of hazardous air pollutants in the San Francisco Bay Area. Environ Health Perspect. 2006;114:1438–44.PubMedCrossRefGoogle Scholar
  3. 3.
    Palmer RF, Blanchard S, Wood R. Proximity to point sources of environmental mercury release as a predictor of autism prevalence. Health Place. 2009;15:18–24.PubMedCrossRefGoogle Scholar
  4. 4.
    Orct T, Blanusa M, Lazarus M, Varnai VM, Kostial K. Comparison of organic and inorganic mercury distribution in suckling rat. J Appl Toxicol. 2006;26:536–9.PubMedCrossRefGoogle Scholar
  5. 5.
    Nordenhäll K, Dock L, Vahter M. Transplacental and lactational exposure to mercury in hamster pups after maternal administration of methyl mercury in late gestation. Pharmacol Toxicol. 1995;77:130–5.PubMedCrossRefGoogle Scholar
  6. 6.
    Oskarsson A, Palminger Hallén I, Sundberg J. Exposure to toxic elements via breast milk. Analyst. 1995;120:765–70.PubMedCrossRefGoogle Scholar
  7. 7.
    Glaser V, Nazari EM, Muller YM, Feksa L, Wannmacher CM, Rocha JB, et al. Effects of inorganic selenium administration in methylmercury-induced neurotoxicity in mouse cerebral cortex. Int J Dev Neurosci. 2010;28:631–7.PubMedCrossRefGoogle Scholar
  8. 8.
    Yin ZZ, Lee E, Ni M, Jiang H, Milatovic D, Rongzhu L, et al. Methylmercury-induced alterations in astrocyte function are attenuated by ebselen. Neurotoxicology. 2011;32(3):291–9.PubMedCrossRefGoogle Scholar
  9. 9.
    Heath JA, Frederick PC. Relationship among mercury concentrations, hormones, and nesting effort of white Ibises (Eudocimus albus) in the Florida Everglades. Auk. 2005;122:255–67.CrossRefGoogle Scholar
  10. 10.
    Tan SW, Meiller JC, Mahaffey KR. The endocrine effects of mercury in humans and wildlife. Crit Rev Toxicol. 2009;39:228–69.PubMedCrossRefGoogle Scholar
  11. 11.
    Chang JY, Tsai PF. Prevention of methylmercury-induced mitochondrial depolarization, glutathione depletion and cell death by 15-deoxy-delta-12,14-prostglandin J(2). Neurotoxicology. 2008;29:1054–61.PubMedCrossRefGoogle Scholar
  12. 12.
    Barcelos GR, Grotto D, Serpeloni JM, Angeli JP, Rocha BA, et al. Protective properties of quercetin against DNA damage and oxidative stress induced by methylmercury in rats. Arch Toxicol. 2011;85(9):1151–7.PubMedCrossRefGoogle Scholar
  13. 13.
    Stringari J, Nunes AK, Franco JL, Bohrer D, Garcia SC, Dafre AL, et al. Prenatal methylmercury exposure hampers glutathione antioxidant system ontogenesis and causes long-lasting oxidative stress in the mouse brain. Toxicol Appl Pharmacol. 2008;227:147–54.PubMedCrossRefGoogle Scholar
  14. 14.
    WHO. The Global Advisory Committee on Vaccine Safety, Statement on thiomersal. http://www.who.int/vaccine_safety/topics/thiomersal/statement_jul2006/en/index.html; 2006.
  15. 15.
    Maier SE, Cramer JA, West JR, Sohrabji F. Alcohol exposure during the first two trimesters equivalent alters granule cell number and neurotropin expression in the developing rat olfactory bulb. J Neurobiol. 1999;41:414–23.PubMedCrossRefGoogle Scholar
  16. 16.
    Bellinger FP, Bedi KS, Wilson P, Wilce PA. Ethanol exposure during the third trimester equivalent results in long-lasting decreased synaptic efficacy but not plasticity in the CA1 region of the rat hippocampus. Synapse. 1999;31:51–8.PubMedCrossRefGoogle Scholar
  17. 17.
    Silva JE, Leonard JL, Crantz FR, Larsen PR. Evidence for two tissue-specific pathways for in vivo thyroxine 5′-deiodination in the rat. J Clin Invest. 1982;69:1176–84.Google Scholar
  18. 18.
    Nguon K, Baxter MG, Sajdel-Sulkowska EM. Perinatal exposure to polychlorinated biphenyls differentially affects cerebellar development and motor functions in male and female rat neonates. Cerebellum. 2005;4:112–22.PubMedCrossRefGoogle Scholar
  19. 19.
    Sajdel-Sulkowska EM, Nguon K, Sulkowski ZL, Rosen GD, Baxter MG. Purkinje cell loss accompanies motor impairment in rats developing at altered gravity. Neuroreport. 2005;16:2037–40.PubMedCrossRefGoogle Scholar
  20. 20.
    Sajdel-Sulkowska EM, Lipinski B, Windom H, Audhya T, McGinnis W. Oxidative stress in autism: cerebellar 3-nitrotyrosine levels. Am J Biochem Biotechnol. 2008;4:73–84.CrossRefGoogle Scholar
  21. 21.
    Zavacki AM, Ying H, Christoffolete MA, Aerts G, So E, Harney JW, et al. Type 1 iodothyronine deiodinase is a sensitive marker of peripheral thyroid status in the mouse. Endocrinology. 2005;146:1568–75.PubMedCrossRefGoogle Scholar
  22. 22.
    Eccles CU, Annau Z. Prenatal methyl mercury exposure: I. Alterations in neonatal activity. Neurobehav Tocicol Teratol. 1982a;4:371–6.Google Scholar
  23. 23.
    Eccles CU, Annau Z. Prenatal methyl mercury exposure: II. Alterations in learning and psychotropic drug sensitivity in adult offspring. Neurobehav Tocicol Teratol. 1982;4:377–82.Google Scholar
  24. 24.
    Morte B, Ceballos A, Diez D, Grijota-Martinez C, Dumitrescu AM, Di Cosmo C, et al. Thyroid hormone-regulated mouse cerebral cortex genes are differentially dependent on the source of the hormone: a study in monocarboxylate transporter-8- and deiodinase-2-deficient mice. Endocrinology. 2010;151:2381–7.PubMedCrossRefGoogle Scholar
  25. 25.
    Zieminska E, Toczylowska B, Stafiej A, Lazarewicz JW. Low molecular weight thiols reduce thimerosal neurotoxicity in vitro: modulation by proteins. Toxicology. 2010;276:154–63.PubMedCrossRefGoogle Scholar
  26. 26.
    Gardner RM, Nyland JF, Silbergeld EK. Differential immunotoxic effects of inorganic and organic mercury species in vitro. Toxicol Lett. 2010;198:182–90.PubMedCrossRefGoogle Scholar
  27. 27.
    Clarkson TW, Magos L, Myers GJ. The toxicology of mercury—current exposures and clinical manifestations. N Eng J Med. 2003;349:1731–7.CrossRefGoogle Scholar
  28. 28.
    Gao Y, Yan CH, Tian Y, Xie HF, Zhou X, Yu XD, et al. Prenatal exposure to mercury and neurobehavioral development of neonates in Zhoushan City, China. Environ Res. 2007;105:390–9.PubMedCrossRefGoogle Scholar
  29. 29.
    Debes F, Budtz-Jørgensen E, Weihe P, White RF, Grandjean P. Impact of prenatal methylmercury exposure on neurobehavioral function at age 14 years. Neurotoxicol Teratol. 2006;28:363–75.PubMedCrossRefGoogle Scholar
  30. 30.
    Kuhnert PM, Kuhnert BR, Erhard P. Comparison of mercury levels in maternal blood, fetal cord blood, and placental tissue. Am J Obstet Gynecol. 1981;139:209–13.PubMedGoogle Scholar
  31. 31.
    Montgomery KS, Mackey J, Thuett K, Ginestra S, Bizon JL, Abbott LC. Chronic, low-dose prenatal exposure to methylmercury impairs motor and mnemonic function in adult C57/B6 mice. Behav Brain Res. 2008;191:55–61.PubMedCrossRefGoogle Scholar
  32. 32.
    Morgan DL, Price HC, Fernando R, Chanda SM, O’Connor RW, Barone Jr SS, et al. Gestational mercury vapor exposure and diet contribute to mercury accumulation in neonatal rats. Environ Health Perspect. 2006;114:735–9.PubMedCrossRefGoogle Scholar
  33. 33.
    Zareba G, Cernichiari E, Hojo R, Nitt SM, Weiss B, Mumtaz MM, et al. Thimerosal distribution and metabolism in neonatal mice: comparison with methyl mercury. J Appl Toxicol. 2007;27:511–8.PubMedCrossRefGoogle Scholar
  34. 34.
    Sakamoto M, Kakita A, de Oliveira RB, Sheng Pan H, Takahashi H. Dose-dependent effects of methylmercury administered during neonatal brain spurt in rats. Brain Res Dev Brain Res. 2004;152:171–6.PubMedCrossRefGoogle Scholar
  35. 35.
    Kodavanti UP, Schladweiler MC, Ledbetter AD, Ortuno RV, Suffia M, Evansky P, et al. The spontaneously hypertensive rat: an experimental model of sulfur dioxide-induced airways disease. Toxicol Sci. 2006;94:193–205.PubMedCrossRefGoogle Scholar
  36. 36.
    Wang X, Desai K, Juurlink BH, de Champlain J, Wu L. Gender-related differences in advanced glycation endproducts, oxidative stress markers and nitric oxide synthases in rats. Kidney Int. 2006;69:281–7.PubMedCrossRefGoogle Scholar
  37. 37.
    Saiki R, Okazaki M, Iwai S, Kumai T, Kobayashi S, Oguchi K. Effects of pioglitazone on increases in visceral fat accumulation and oxidative stress in spontaneously hypertensive hyperlipidemic rats fed a high-fat diet and sucrose solution. J Pharmacol Sci. 2007;105:157–67.PubMedCrossRefGoogle Scholar
  38. 38.
    Beyrouty P, Stamler CJ, Liu JN, Loua KM, Kubow S, Chan HM. Effects of prenatal methylmercury exposure on brain monoamine oxidase activity and neurobehaviour of rats. Neurotocicol Teratol. 2006;28:251–9.CrossRefGoogle Scholar
  39. 39.
    Roegge CS, Morris JR, Villareal S, Wang VC, Powers BE, Klintsova AY, et al. Purkinje cell and cerebellar effects following developmental exposure to PCBs and/or MeHg. Neurotocicol Teratol. 2006;28:74–85.CrossRefGoogle Scholar
  40. 40.
    Ueha-Ishibashi T, Oyama Y, Nakao H, Umebayashi C, Nishizaki Y, Tatsuishi T, et al. Effect of thimerosal, a preservative in vaccines, on intracellular Ca2+ concentration of rat cerebellar neurons. Toxicology. 2004;195:77–84.PubMedCrossRefGoogle Scholar
  41. 41.
    Linares AF, Loikkanen J, Jorge MF, Soria RB, Novoa AV. Antioxidant and neuroprotective activity of the extract from the seaweed, Halimeda incrassata (Ellis) Lamouroux, against in vitro and in vivo toxicity induced by methyl-mercury. Vet Hum Toxicol. 2004;46:1–5.PubMedGoogle Scholar
  42. 42.
    Kaur P, Aschner M, Syversen T. Glutathione modulation influences methyl mercury induced neurotoxicity in primary cell cultures of neurons and astrocytes. Neurotoxicology. 2006;27:492–500.PubMedCrossRefGoogle Scholar
  43. 43.
    Rush T, Hjelmhaug J, Lobner D. Effects of chelators on mercury, iron, and lead neurotoxicity in cortical culture. Neurotoxicology. 2009;30:47–51.PubMedCrossRefGoogle Scholar
  44. 44.
    Vicente E, Boer M, Netto C, Fochesatto C, Dalmaz C, Rodrigues Siqueira I, et al. Hippocampal antioxidant system in neonates from methylmercury-intoxicated rats. Neurotoxicol Teratol. 2004;26:817–23.PubMedCrossRefGoogle Scholar
  45. 45.
    Sajdel-Sulkowska EM. Oxidative stress and neurotrophin signaling in autism. In: Chauhan A, Chauhan V, Brown WT, editors. Autism: oxidative stress, inflammation and immune abnormalities. Boca Raton, FL: CRC; 2010. p. 47–60.Google Scholar
  46. 46.
    Beal MF. Oxidatively modified proteins in aging and disease. Free Radic Biol Med. 2002;32:797–803.PubMedCrossRefGoogle Scholar
  47. 47.
    Neumann H, Hazen L, Weinstein J, Mehl RA, Chin JW. Genetically encoding protein oxidative damage. J Am Chem Soc. 2008;130:4028–33.PubMedCrossRefGoogle Scholar
  48. 48.
    Gereben B, Zavacki AM, Ribich S, Kim BW, Huang SA, Simonides WS, et al. Cellular and molecular basis of deiodinase-regulated thyroid hormone signaling. Endocr Rev. 2008;29:898–938.PubMedCrossRefGoogle Scholar
  49. 49.
    Galton VA, Wood ET, St Germain EA, Withrow CA, Aldrich G, St Germain GM, et al. Thyroid hormone homeostasis and action in the type 2 deiodinase-deficient rodent brain during development. Endocrinology. 2007;148:3080.PubMedCrossRefGoogle Scholar
  50. 50.
    Goldey ES, Kehn LS, Rehnberg GL, Crofton KM. Effects of developmental hypothyroidism on auditory and motor function in the rat. Toxicol Appl Pharmacol. 1995;135:67–76.PubMedCrossRefGoogle Scholar
  51. 51.
    Ng L, Goodyear RJ, Woods CA, Schneider MJ, Diamond E, Richardson GP, et al. Hearing loss and retarded cochlear development in mice lacking type 2 iodothyronine deiodinase. Proc Natl Acad Sci U S A. 2004;101:3474–9.PubMedCrossRefGoogle Scholar
  52. 52.
    Soldin OP, O’Mara DM, Aschner M. Thyroid hormones and methylmercury toxicity. Biol Trace Elem Res. 2008;126:1–12.PubMedCrossRefGoogle Scholar
  53. 53.
    Watanabe C. Selenium deficiency and brain functions: the significance for methylmercury toxicity. Nippon Eiseigaku Zasshi. 2001;55:581–9.PubMedCrossRefGoogle Scholar
  54. 54.
    Lamirand A, Pallud-Mothré S, Ramaugé M, Pierre M, Courtin F. Oxidative stress regulates type 3 deiodinase and type 2 deiodinase in cultured rat astrocytes. Endocrinology. 2008;149:3713–21.PubMedCrossRefGoogle Scholar
  55. 55.
    Kim CY, Watanabe C, Satoh H. Effects of buthionine sulfoximine (BSO) on mercury distribution after Hg(o) exposure. Toxicology. 1995;98:67–72.PubMedCrossRefGoogle Scholar
  56. 56.
    James SJ, Slikker 3rd W, Melnyk S, New E, Pogribna M, Jernigan S. Thimerosal neurotoxicity is associated with glutathione depletion: protection with glutathione precursors. Neurotoxicology. 2005;26:1–8.PubMedCrossRefGoogle Scholar
  57. 57.
    Goswami A, Rosenberg I. Effects of glutathione on iodothyronine 5′-deiodinase activity. Endocrinology. 1988;123:192–202.PubMedCrossRefGoogle Scholar
  58. 58.
    Croteau W, Bodwell JE, Richardson JM, St Germain DL. Conserved cysteines in the type 1 deiodinase selenoprotein are not essential for catalytic activity. J Biol Chem. 1998;273:25230–6.PubMedCrossRefGoogle Scholar
  59. 59.
    Goemann IM, Gereben B, Harney JW, Zhu B, Maia AL, Larsen PR. Substitution of serine for proline in the active center of type 2 iodothyronine deiodinase substantially alters its in vitro biochemical properties with dithiothreitol but not its function in intact cells. Endocrinology. 2010;151:821–9.PubMedCrossRefGoogle Scholar
  60. 60.
    Dasgupta A, Das S, Sarkar PK. Thyroid hormone promotes glutathione synthesis in astrocytes by up regulation of glutamate cysteine ligase through differential stimulation of its catalytic and modulator subunit mRNAs. Free Radic Biol Med. 2007;42:617–26.PubMedCrossRefGoogle Scholar
  61. 61.
    Sobutskii MP, Kovan’ko EG, Liutinskii SI, Ivanov SD. Effect of age and gender on genotoxic and biochemical indexes in animal blood after low doses of radiation-mercury exposure. Adv Gerontol. 2007;20:91–6.PubMedGoogle Scholar
  62. 62.
    Olczak M, Duszczyk M, Mierzejewski P, Majewska MD. Neonatal administration of a vaccine preservative, thimerosal, produces lasting impairment of nociception and apparent activation of opioid system in rats. Brain Res. 2009;1301:143–51.PubMedCrossRefGoogle Scholar
  63. 63.
    Holmes E, Nicholls AW, Lindon JC, Connor SC, Connelly JC, Haselden JN, et al. Chemometric models for toxicity classification based on NMR spectra of biofluids. Chem Res Toxicol. 2000;13:471–8.PubMedCrossRefGoogle Scholar
  64. 64.
    Gundacker C, Gencik M, Hengstschläger M. The relevance of the individual genetic background for the toxicokinetics of two significant neurodevelopmental toxicants: mercury and lead. Mutat Res. 2010;705:130–40.PubMedCrossRefGoogle Scholar
  65. 65.
    Ballerio R, Gianazza E, Mussoni L, Miller I, Gelosa P, Guerrini U, et al. Gender differences in endothelial function and inflammatory markers along the occurrence of pathological events in stroke-prone rats. Exp Mol Pathol. 2007;82:33–41.PubMedCrossRefGoogle Scholar
  66. 66.
    Agnish ND, Keller KA. The rationale for culling of rodent litters. Fundam Appl Toxicol. 1997;38:2–6.PubMedCrossRefGoogle Scholar
  67. 67.
    Palmer AK, Ulbrich BC. The cult of culling. Fundam Appl Toxicol. 1997;38:7–22.PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  • Z. L. Sulkowski
    • 1
  • T. Chen
    • 2
  • S. Midha
    • 1
  • A. M. Zavacki
    • 2
  • Elizabeth M. Sajdel-Sulkowska
    • 1
    • 3
  1. 1.Department of PsychiatryHarvard Medical School and Brigham and Women’s HospitalBostonUSA
  2. 2.Thyroid Section, Division of Endocrinology, Diabetes and Hypertension, Department of MedicineHarvard Medical School and Brigham and Women’s HospitalBostonUSA
  3. 3.Department of Psychiatry BWHHarvard Institute of MedicineBostonUSA

Personalised recommendations