Fluoride-Free Diet Stimulates Pineal Growth in Aged Male Rats
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.
KeywordsPineal gland Pinealocytes Melatonin Calcification Fluoride Fluoridation Drinking water Aging Neurodegenerative disease
Dr. Thomas P. Diggins (Department of Biological Sciences, Youngstown State University) assisted with the statistical analysis.
Mrvelj A and Womble MD designed and conceived the study. Mrvelj A performed the experiments and data analysis. Mrvelj A and Womble MD drafted and approved the manuscript.
Compliance with Ethical Standards
Conflict of Interest
This study was supported by a Youngstown State University Research Council grant to MDW and a Cushwa-Commericial Shearing Graduate Fellowship to AM. The authors declare that there is no conflict of interest associated with this manuscript.
Animal use adhered to the Guide for the Care and Use of Laboratory Animals (8th edition, National Research Council, 2011) and was approved by the Youngstown State University’s Institutional Animal Care and Use Committee (protocol #04-16).
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