Fluoride Action Network

Abstract

The pineal gland is a naturally calcifying endocrine organ which secretes the sleep-promoting hormone melatonin. Age-related changes of the pineal have been observed, including decreased pinealocyte numbers, increased calcification, and a reduction in melatonin production. Since fluoride is attracted to calcium within the pineal gland, this study sought to examine the effects of a fluoride-free diet on the morphology of the pineal gland of aged male rats (26 months old). All animals had previously been raised on standard fluoridated food and drinking water. These control animals were compared to other animals that were placed on a fluoride-free diet (“fluoride flush”) for 4 or 8 weeks. At 4 weeks, pineal glands from fluoride-free animals showed a 96% increase in supporting cell numbers and at 8 weeks a 73% increase in the number of pinealocytes compared to control animals. In contrast, the number of pinealocytes and supporting cells in animals given an initial 4-week fluoride flush followed by a return to fluoridated drinking water (1.2 ppm NaF) for 4 weeks were not different from control animals. Our findings therefore demonstrate that a fluoride-free diet encouraged pinealocyte proliferation and pineal gland growth in aged animals and fluoride treatment inhibited gland growth. These findings suggest that dietary fluoride may be detrimental to the pineal gland.

References

  1. Allen DJ, DiDio LJA, Gentry ER, Ohtani O (1982) The aged rat pineal gland as revealed in SEM and TEM. Age 5(4):119–126.  https://doi.org/10.1007/BF02431274 CrossRefGoogle Scholar
  2. Bastianelli E, Pochet R (1993) Sexual dimorphism among calbindin-D28K immunoreactive cells in the rat pineal body. Histochem 100:449–455.  https://doi.org/10.1007/BF00267825 CrossRefGoogle Scholar
  3. Redecker P (1993) Dense accumulations of synaptic-like microvesicles in dark pinealocytes of the gerbil pineal gland. J Neurocytol 22(7):572–581.  https://doi.org/10.1007/bf01189044 CrossRefPubMedPubMedCentralGoogle Scholar
  4. Prosenc N, Cervos-Navarro J (1994) Ultrastructural morphology of the aged pineal. Ann N Y Acad Sci 719:64–76.  https://doi.org/10.1111/j.1749-6632.1994.tb56820.x CrossRefPubMedPubMedCentralGoogle Scholar
  5. Al-Hussain S (2006) The pinealocytes of the human pineal gland: a light and electron microscopic study. Via Medica 65(3):181–187Google Scholar
  6. Calvo J, Boya J (1984) Postnatal evolution of the rat pineal gland: light microscopy. J Anat. 138(1):45–53PubMedPubMedCentralGoogle Scholar
  7. Rath MF, Coon SL, Amaral FG, Weller JL, Møller M, Klein DC (2016) Melatonin synthesis: acetylserotonin O-methyltransferase (ASMT) is strongly expressed in a subpopulation of pinealocytes in the male rat pineal gland. Endocrinol 157(5):2028–2040.  https://doi.org/10.1210/en.2015-1888 CrossRefGoogle Scholar
  8. Mays JC, Kelly MC, Coon SL, Holtzclaw L, Rath MF, Kelley MW, Klein DC (2018) Single-cell RNA sequencing of the mammalian pineal gland identifies two pinealocyte subtypes and cell type-specific daily patterns of gene expression. PLoS One 13(10):e0205883.  https://doi.org/10.1371/journal.pone.0205883 CrossRefPubMedPubMedCentralGoogle Scholar
  9. Møller M, Baeres FM (2002) The anatomy and innervation of the mammalian pineal gland. Cell Tissue Res. 309:139–150.  https://doi.org/10.1007/s00441-002-0580-5 CrossRefPubMedPubMedCentralGoogle Scholar
  10. Ibañez Rodriguez MP, Noctor SC, Muñoz EM (2016) Cellular basis of pineal gland development: emerging role of microglia as phenotype regulator. PloS One 11(11):e0167063–e0167063.  https://doi.org/10.1371/journal.pone.0167063 CrossRefGoogle Scholar
  11. Hasegawa A, Mori W (1980) Morphometry of the human pineal gland: relationship to the adrenal cortex. Pathol Int 30(3):407–410.  https://doi.org/10.1111/j.1440-1827.1980.tb01335.x CrossRefGoogle Scholar
  12. Nölte I, Lütkhoff A-T, Stuck BA, Lemmer B, Schredl M, Findeisen P, Groden C (2009) Pineal volume and circadian melatonin profile in healthy volunteers: an interdisciplinary approach. J Magn Reson Imaging 30:499–505.  https://doi.org/10.1002/jmri.21872 CrossRefPubMedPubMedCentralGoogle Scholar
  13. Matsuoka T, Imai A, Fujimoto H, Kato Y, Shibata K, Nakamura K, Yokota H, Yamada K, Narumoto J (2017) Reduced pineal volume in Alzheimer disease: a retrospective cross-sectional MR imaging study. Radiology 286(1):239–248.  https://doi.org/10.1148/radiol.2017170188 CrossRefPubMedPubMedCentralGoogle Scholar
  14. Gheban BA, Rosca IA, Crisan M (2019) The morphological and functional characteristics of the pineal gland. Med Pharm Reports 92(3):226–234.  https://doi.org/10.15386/mpr-1235 CrossRefGoogle Scholar
  15. Singh R, Ghosh S, Joshi A, Haldar C (2014) Human pineal gland: histomorphological study in different age groups and different causes of death. J Anat Soc India 63:98–102.  https://doi.org/10.1016/j.jasi.2014.11.004 CrossRefGoogle Scholar
  16. Reuss S, Spies C, Schroder H, Vollrath L (1990) The aged pineal gland: reduction in pinealocyte number and adrenergic innervation in male rats. Exp Gerontol 25(2):183–188.  https://doi.org/10.1016/0531-5565(90)90049-8 CrossRefPubMedPubMedCentralGoogle Scholar
  17. Liebrich L, Schredl M, Findeisen P, Groden C, Bumb J, Nölte I (2013) Morphology and function: MR pineal volume and melatonin level in human saliva are correlated. J Magn Reson Imaging 40(4):966–971.  https://doi.org/10.1002/jmri.24449 CrossRefPubMedPubMedCentralGoogle Scholar
  18. Pang SF, Tang F, Tang PL (1984) Negative correlation of age and the levels of pineal melatonin, pineal N-acetylserotonin, and serum melatonin in male rats. J Exp Zool 229:41–47.  https://doi.org/10.1002/jez.1402290106 CrossRefPubMedPubMedCentralGoogle Scholar
  19. Sack RL, Lewy AJ, Erb DL, Vollmer WM, Singer CM (1986) Human melatonin production decreases with age. J Pineal Res 3:379–388.  https://doi.org/10.1111/j.1600-079X.1986.tb00760.x CrossRefPubMedPubMedCentralGoogle Scholar
  20. Mahlberg R, Kienast T, Hädel S, Heidenreich JO, Schmitz S, Kunz D (2009) Degree of pineal calcification (DOC) is associated with polysomnographic sleep measures in primary insomnia patients. Sleep Med 10(4):439–445.  https://doi.org/10.1016/j.sleep.2008.05.003 CrossRefPubMedPubMedCentralGoogle Scholar
  21. Humbert W, Pevet P (1994) The decrease of pineal melatonin production with age: causes and consequences. NY Acad Sci 719:43–63.  https://doi.org/10.1111/j.1749-6632.1994.tb56819.x CrossRefGoogle Scholar
  22. Humbert W, Pevet P (1995) The pineal gland of the aging rat: calcium localization and variation in the number of pinealocytes. J Pineal Res 18(1):32–40CrossRefGoogle Scholar
  23. Dekar-Madoui A, Besseau L, Magnanou E, Fons R, Ouali S, Bendjelloul M, Falcon J (2012) Cellular aspects of aging in the pineal gland of the shrew, Crocidura russula. C R Biol 335(1):9–18.  https://doi.org/10.1016/j.crvi.2011.11.001 CrossRefPubMedPubMedCentralGoogle Scholar
  24. Humbert W, Pevet P (1995) Calcium concretions in the pineal gland of aged rats: an ultrastructural and microanalytical study of their biogenesis. Cell Tiss Res 279(3):565–573.  https://doi.org/10.1007/s004410050315 CrossRefGoogle Scholar
  25. 25.
    Luke J (2001) Fluoride deposition in the aged human pineal gland. Caries Res 35(2):125–128.  https://doi.org/10.1159/000047443 CrossRefPubMedPubMedCentralGoogle Scholar
  26. Bulc M, Lewczuk B, Prusik M, Gugo A (2010) Calcium concrements in the pineal gland of the Arctic fox (Vulpes lagopus) and their relationship to pinealocytes, glial cells and type I and III collagen fibers. Pol J Vet Sci 13(2):269–278PubMedPubMedCentralGoogle Scholar
  27. Kim JW, Kim H-W, Chang S, Je JH, Rhyu IJ (2012) Growth patterns for acervuli in human pineal gland. Sci Rep 2(984):1–5.  https://doi.org/10.1038/srep00984 CrossRefGoogle Scholar
  28. Gerasimov AV, Kostyuchenko VP, Solovieva AS, Olovnikov AM (2014) Pineal gland as an endocrine gravitational lunasensor: manifestation of moon phase dependent morphological changes in mice. Biokhimiya 79(10):1069–1074.  https://doi.org/10.1134/S0006297914100083 CrossRefGoogle Scholar
  29. Tan DX, Xu B, Zhou X, Reiter RJ (2018) Pineal calcification, melatonin production, aging, associated health consequences and rejuvenation of the pineal gland. Molecules 23:301–332.  https://doi.org/10.3390/molecules23020301 CrossRefGoogle Scholar
  30. Luke JA (1997) The effect of fluoride on the physiology of the pineal gland. PhD Dissertation, School of Biological Sciences, University of Surrey, UK.Google Scholar
  31. Anti? S, Jovanovi? I, Stefanovi? N, Pavlovi? S, Ran?i? G, Ugrenovi? S (2004) Morphology and histochemical characteristics of human pineal gland acervuli during aging. Facta Univ Ser Med Biol 11(2):63–68 UC 612.43:612.67Google Scholar
  32. Arunkumar KG, Amar Jayanthi A, Indira CK, Girijamony VK (2015) Age- and sex-related changes in pineal gland: A morphological and histological study. Am J Intern Med 3(6-1):10–13.  https://doi.org/10.11648/j.ajim.s.2015030601.13 CrossRefGoogle Scholar
  33. Mahlberg R, Walther S, Kalus P, Bohner G, Haedel S, Reischies FM, Kuhl K-P, Hellweg R, Kunz D (2008) Pineal calcification in Alzheimer’s disease: an in vivo study using computed tomography. Neurobiol Aging 29:203–209.  https://doi.org/10.1016/j.neurobiolaging.2006.10.003 CrossRefGoogle Scholar
  34. Hardeland R, Cardinali DP, Brown GM, Pandi-Perumal SR (2015) Melatonin and brain inflammaging. Prog Neurobiol 127–128:46–63.  https://doi.org/10.1016/j.pneurobio.2015.02.001 CrossRefGoogle Scholar
  35. Beriwal N, Namgyal T, Sangay P, Al Quraan AM (2019) Role of immune-pineal axis in neurodegenerative diseases, unraveling novel hybrid dark hormone therapies. Heliyon 5(1):e01190–e01190.  https://doi.org/10.1016/j.heliyon.2019.e01190 CrossRefPubMedPubMedCentralGoogle Scholar
  36. Blinkhorn AS, Byun R, Johnson G, Metha P, Kay M, Lewis P (2015) The dental health of primary school children living in fluoridated, pre-fluoridated and non-fluoridated communities in New South Wales, Australia. BMC Oral Health 15:9.  https://doi.org/10.1186/1472-6831-15-9 CrossRefPubMedPubMedCentralGoogle Scholar
  37. Centers for Disease Control and Prevention (1999) Achievements in public health, 1900-1999: fluoridation of drinking water to prevent dental caries. Morb Mortal Wkly Rep 48(41):933–940 www.cdc.gov/mmwr/preview/mmwrhtml/mm4841a1.htm Google Scholar
  38. National Research Council (2006) Fluoride in drinking water: a scientific review of EPA’s standards. The National Academies Press, Washington DC. doi.org/10.17226/11571.
  39. Czajka M (2012) Systemic Effects of Fluoridation. J Orthomol Med 27(3):123–131Google Scholar
  40. Peckham S, Awofeso N (2014) Water fluoridation: a critical review of the physiological effects of ingested fluoride as a public health intervention. Sci World J 2014:293019.  https://doi.org/10.1155/2014/293019 CrossRefGoogle Scholar
  41. Iheozor-Ejiofor Z, Worthington HV, Walsh T, O’Malley L, Clarkson JE, Macey R, Glenny A-M (2015) Water fluoridation for the prevention of dental caries. Cochrane Database Sys Rev 6:Art. No.: CD010856.  https://doi.org/10.1002/14651858.CD010856.pub2 CrossRefGoogle Scholar
  42. Akinrinade ID, Memudu AE, Ogundele OM (2015) Fluoride and aluminum disturb neuronal morphology, transport functions, cholinesterase, lysosomal and cell cycle activities. Pathophysiol 22(2):105–115.  https://doi.org/10.1016/j.pathophys.2015.03.001 CrossRefGoogle Scholar
  43. Zhou Y, Qiu Y, He J, Chen X, Ding Y, Wang Y, Liu X (2013) The toxicity mechanism of sodium fluoride on fertility in female rats. Food Chem Toxicol 62:566–572.  https://doi.org/10.1016/j.fct.2013.09.023 CrossRefPubMedPubMedCentralGoogle Scholar
  44. Zhou Y, Zhang H, He J, Chen X, Ding Y, Wang Y, Liu X (2013) Effects of sodium fluoride on reproductive function in female rats. Food Chem Toxicol 56:297–303.  https://doi.org/10.1016/j.fct.2013.02.026 CrossRefPubMedPubMedCentralGoogle Scholar
  45. Zhang J, Zhu Y, Liang C, Qie M, Niu R, Sun Z, Wang J, Wang J (2017) Effects of fluoride on expression of P450, CREM and ACT proteins in rat testes. Biol Trace Elem Res 175(1):156–160.  https://doi.org/10.1007/s12011-016-0753-9 CrossRefPubMedPubMedCentralGoogle Scholar
  46. Kalisinska E, Natalia IB, Bird ÁBÁ (2014) Fluoride concentrations in the pineal gland, brain and bone of goosander (Mergus merganser) and its prey in Odra River estuary in Poland. Environ Geochem Health 36:1063–1077.  https://doi.org/10.1007/s10653-014-9615-6 CrossRefPubMedPubMedCentralGoogle Scholar
  47. National Research Council (2011) Guide for the Care and Use of Laboratory Animals, 8th edn. The National Academies Press, Washington DC.  https://doi.org/10.17226/12910 CrossRefGoogle Scholar
  48. Humason GL (1979) Animal Tissue Techniques, 4th edn. W.H. Freeman, San FranciscoGoogle Scholar
  49. Becker UG, Vollrath L (1983) 24-Hour-variation of pineal gland volume, pinealocyte nuclear volume and mitotic activity in male sprague-dawley rats. J. Neural Transmission 56:211–221.  https://doi.org/10.1007/BF01243279 CrossRefGoogle Scholar
  50. Calvo JL, Boya J, Carbonell AL, Garcia-Mauriiio JE (1997) Influence of the light and dark phase of the cycle on the cellular proliferation in the pineal gland of the adult rat: a bromodeoxyuridine immunohistochemical study. J. Pineal Res. 23:1–4.  https://doi.org/10.1111/j.1600-079x.1997.tb00327.x CrossRefPubMedPubMedCentralGoogle Scholar
  51. Karasek M, Marek K, Pévet P (1988) Influence of a short light pulse at night on the ultrastructure of the rat pinealocyte: a quantitative study. Cell Tiss Res 254(1):247–249.  https://doi.org/10.1007/BF00220041 CrossRefGoogle Scholar
  52. Bharti VK, Srivastava RS (2009) Fluoride-induced oxidative stress in rat’s brain and its amelioration by buffalo (Bubalus bubalis) pineal proteins and melatonin. Biol Trace Elem Res 130(2):131–140.  https://doi.org/10.1007/s12011-009-8320-2 CrossRefPubMedPubMedCentralGoogle Scholar
  53. Bharti VK, Srivastava RS (2010) Effects of epiphyseal proteins and melatonin on blood biochemical parameters of fluoride-intoxicated rats. Neurophysiol 42(4):309–315.  https://doi.org/10.1007/s11062-011-9158-8 CrossRefGoogle Scholar