Fluoride Toxicity and Status of Serum Thyroid Hormones, Brain Histopathology, and Learning Memory in Rats: A Multigenerational Assessment

Abstract

High-fluoride (100 and 200 ppm) water was administered to rats orally to study the fluoride-induced changes on the thyroid hormone status, the histopathology of discrete brain regions, the acetylcholine esterase activity, and the learning and memory abilities in multigeneration rats. Significant decrease in the serum-free thyroxine (FT4) and free triiodothyronine (FT3) levels and decrease in acetylcholine esterase activity in fluoride-treated group were observed. Presence of eosinophilic Purkinje cells, degenerating neurons, decreased granular cells, and vacuolations were noted in discrete brain regions of the fluoride-treated group. In the T-maze experiments, the fluoride-treated group showed poor acquisition and retention and higher latency when compared with the control. The alterations were more profound in the third generation when compared with the first- and second-generation fluoride-treated group. Changes in the thyroid hormone levels in the present study might have imbalanced the oxidant/antioxidant system, which further led to a reduction in learning memory ability. Hence, presence of generational or cumulative effects of fluoride on the development of the offspring when it is ingested continuously through multiple generations is evident from the present study.

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Acknowledgment

The authors thank the University Grants Commission, New Delhi, India, for research grants (F. no. 31-220/2005 (SR) dated 31-03-2006 and MRP(S)/139/08-09/KABA027/UGC/SWRO).

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Correspondence to Piler Mahaboob Basha.

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Basha, P.M., Rai, P. & Begum, S. Fluoride Toxicity and Status of Serum Thyroid Hormones, Brain Histopathology, and Learning Memory in Rats: A Multigenerational Assessment. Biol Trace Elem Res 144, 1083–1094 (2011). https://doi.org/10.1007/s12011-011-9137-3

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Keywords

  • Fluoride
  • Multigenerational effects