The Effects of Early Exposure to Thimerosal on Impairments of Social and Stereotyped Behaviors and the Number of Purkinje Cells of Cerebellum in Rats

Document Type: Original Article

Authors

1 Institute for Cognitive Science Studies (ICSS), Tehran, Iran

2 Department of Biology and Anatomical Sciences, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran

3 Cognitive and Neuroscience Research Center (CNRC), Tehran Medical Sciences Branch, Islamic Azad University, Tehran, Iran

Abstract

Introduction: Existing evidence on the impact of thimerosal (THIM), acting to preserve pharmaceutical products (a preservative), on fetal neurodevelopment is very controversial. Here, we investigated the neonatal administration of THIM on behaviors including (1) locomotor activity, (2) social behaviors, and (3) stereotyped behaviors in rats. Since the development of cerebellum continues for some time after birth and it is very imperative in movement, balance, and sensory integration, the number of cerebellum Purkinje cells also were counted.
Materials and Methods: The experiments were directed on 40 young male and female Wistar rats, which were randomly distributed into 4 groups including experimental (male & female) and control (male & female) groups. Each rat in the test groups were intramuscularly received 240 μg Hg/kg THIM on postnatal days (7, 9, 11, 15), while the control contributors received saline in the same pattern. After drug interventions on the fourth postnatal week, rats were evaluated by open field test, and in eighth postnatal week, the test of three-chamber paradigm was performed on animals. At the end of the behavioral tests, histological studies were done.
Results: Rats which were exposed to the THIM displayed impairments of locomotor activity and their social interactions were reduced. While the duration of freezing/grooming as stereotyped behaviors were increased significantly. The results of histological studies also showed a noteworthy decrease in the number of Purkinje cells in both sexes.
Conclusions: These data prove that early postnatal exposure of children to THIM causes permanent neurobehavioral and histological impairments and if similar alterations occur in children exposed to THIM/mercurial agents, neurodevelopmental disorders may happen.

Keywords


  1. Geier DA, Kern JK, King PG, Sykes LK, Geier MR. A case-control study evaluating the relationship between thimerosal-containing haemophilus influenzae type b vaccine administration and the risk for a pervasive developmental disorder diagnosis in the United States. Biol Trace Elem Res. 2015;163(1-2):28-38. doi:10.1007/ s12011-014-0169-3.
  2. Barregard L, Rekic D, Horvat M, Elmberg L, Lundh T, Zachrisson O. Toxicokinetics of mercury after long-term repeated exposure to thimerosal-containing vaccine. Toxicol Sci. 2011;120(2):499-506. doi:10.1093/toxsci/kfr009.
  3. Dorea JG, Marques RC, Isejima C. Neurodevelopment of Amazonian infants: antenatal and postnatal exposure to methyl-and ethylmercury. J Biomed Biotechnol. 2012;2012:132876. doi:10.1155/2012/132876.
  4. Geier DA, King PG, Hooker BS, et al. Thimerosal: clinical, epidemiologic and biochemical studies. Clin Chim Acta. 2015;444:212-220. doi:10.1016/j.cca.2015.02.030.
  5. Kidd PM. Autism, an extreme challenge to integrative medicine. Part 2: medical management. Altern Med Rev. 2002;7(6):472-499.
  6. Hewitson L, Lopresti BJ, Stott C, Mason NS, Tomko J. Influence of pediatric vaccines on amygdala growth and opioid ligand binding in rhesus macaque infants: A pilot study. Acta Neurobiol Exp (Wars). 2010;70(2):147-164.
  7. Gallagher C, Goodman M. Hepatitis B triple series vaccine and developmental disability in US children aged 1–9 years. Toxicol Environ Chem. 2008;90(5):997-1008. doi:10.1080/02772240701806501.
  8. Geier DA, Geier MR. A prospective assessment of porphyrins in autistic disorders: a potential marker for heavy metal exposure. Neurotox Res. 2006;10(1):57-64. doi:10.1007/BF03033334.
  9. Geier DA, Hooker BS, Kern JK, King PG, Sykes LK, Geier MR. A dose-response relationship between organic mercury exposure from thimerosal-containing vaccines and neurodevelopmental disorders. Int J Environ Res Public Health. 2014;11(9):9156-9170. doi:10.3390/ijerph110909156.
  10. Geier MR, Geier DA. Neurodevelopmental disorders after thimerosal-containing vaccines: a brief communication. Exp Biol Med (Maywood). 2003;228(6):660-664. doi :10.1177/153537020322800603.
  11. Burket RC, Schramm LL. Therapists’ attitudes about treating patients with eating disorders. South Med J. 1995;88(8):813-818.
  12. Kern JK, Geier DA, Sykes LK, Haley BE, Geier MR. The relationship between mercury and autism: A comprehensive review and discussion. J Trace Elem Med Biol. 2016;37:8-24. doi:10.1016/j.jtemb.2016.06.002.
  13. Kern JK, Geier DA, Audhya T, King PG, Sykes LK, Geier MR. Evidence of parallels between mercury intoxication and the brain pathology in autism. Acta Neurobiol Exp (Wars). 2012;72(2):113- 153.
  14. Carneiro MF, Souza JM, Grotto D, Batista BL, de Oliveira Souza VC, Barbosa F Jr. A systematic study of the disposition and metabolism of mercury species in mice after exposure to low levels of thimerosal (ethylmercury). Environ Res. 2014;134:218- 227.
  15. Olczak M, Duszczyk M, Mierzejewski P, Bobrowicz T, Majewska MD. Neonatal administration of thimerosal causes persistent changes in mu opioid receptors in the rat brain. Neurochem Res. 2010;35(11):1840-1847. doi:10.1007/s11064-010-0250-z.
  16. Olczak M, Duszczyk M, Mierzejewski P, Wierzba-Bobrowicz T, Majewska MD. Lasting neuropathological changes in rat brain after intermittent neonatal administration of thimerosal. Folia Neuropathol. 2010;48(4):258-269.
  17. Olczak M, Duszczyk M, Mierzejewski P, Meyza K, Majewska MD. Persistent behavioral impairments and alterations of brain dopamine system after early postnatal administration of thimerosal in rats. Behav Brain Res. 2011;223(1):107-118. doi:10.1016/j.bbr.2011.04.026.
  18. Laurente J, Remuzgo F, Avalos B, et al. Neurotoxic effects of thimerosal at vaccines doses on the encephalon and development in 7 days-old hamsters. An Fac Med Lima. 2007;68(3):222-237.
  19. Hornig M, Chian D, Lipkin WI. Neurotoxic effects of postnatal thimerosal are mouse strain dependent. Mol Psychiatry. 2004;9(9):833-845. doi:10.1038/sj.mp.4001529.
  20. Namvarpour Z, Nasehi M, Amini A, Zarrindast MR. Protective role of alpha-lipoic acid in impairments of social and stereotyped behaviors induced by early postnatal administration of thimerosal in male rat. Neurotoxicol Teratol. 2018;67:1-9. doi:10.1016/j.ntt.2018.02.002.
  21. Noorafshan A, Erfanizadeh M, Karbalay-Doust S. Stereological studies of the effects of sodium benzoate or ascorbic acid on rats` cerebellum. Saudi Med J. 2014;35(12):1494-1500.
  22. Gerfen CR, Rogawski MA, Sibrey DR, Skolnick P, Wray S. Short Protocols in Neuroscience: Systems and Behavioral Methods. Hoboken: John Wiley; 2006:610.
  23. Sulkowski ZL, Chen T, Midha S, Zavacki AM, Sajdel-Sulkowska EM. Maternal thimerosal exposure results in aberrant cerebellar oxidative stress, thyroid hormone metabolism, and motor behavior in rat pups; sex- and strain-dependent effects. Cerebellum. 2012;11(2):575-586. doi:10.1007/s12311-011-0319-5.
  24. Gandhi D, Dhull DK. Postnatal Behavioural Effects on the Progeny of Rat after Prenatal Exposure to Methylmercury. Am J Exp Biol. 2014;1(1):31-51.
  25. Minami T, Miyata E, Sakamoto Y, Yamazaki H, Ichida S. Induction of metallothionein in mouse cerebellum and cerebrum with low-dose thimerosal injection. Cell Biol Toxicol. 2010;26(2):143-152. doi:10.1007/s10565-009-9124-z.
  26. Li B, Zhang Y, Ma D, Shi Z, Ma S. Mercury nano-trap for effective and efficient removal of mercury(II) from aqueous solution. Nat Commun. 2014;5:5537. doi:10.1038/ncomms6537.
  27. Lewis MH, Tanimura Y, Lee LW, Bodfish JW. Animal models of restricted repetitive behavior in autism. Behav Brain Res. 2007;176(1):66-74. doi:10.1016/j.bbr.2006.08.023.
  28. Afsordeh K, Sadeghi Y, Amini A, et al. Alterations of neuroimmune cell density and pro-inflammatory cytokines in response to thimerosal in prefrontal lobe of male rats. Drug Chem Toxicol. 2018:1-11. doi:10.1080/01480545.2018.1465949.
  29. de Oliveira Souza VC, de Marco KC, Laure HJ, Rosa JC, Barbosa F Jr. A brain proteome profile in rats exposed to methylmercury or thimerosal (ethylmercury). J Toxicol Environ Health A. 2016;79(12):502-512. doi:10.1080/15287394.2016.1182003.
  30. Mutkus L, Aschner JL, Syversen T, Shanker G, Sonnewald U, Aschner M. In vitro uptake of glutamate in GLAST- and GLT-1-transfected mutant CHO-K1 cells is inhibited by the ethylmercury-containing preservative thimerosal. Biol Trace Elem Res. 2005;105(1-3):71- 86. doi:10.1385/bter:105:1-3:071.