Fluoride Action Network



  • Pregnant mice were exposed to environmentally relevant doses of sodium fluoride from GD1 to GD20.
  • Exposure to sodium fluoride resulted in structural and functional impairments in male offspring mouse hippocampus.
  • The activation of P-Creb1 signaling pathway played a role in sodium fluoride-induced cognitive impairment.
  • We provided new insight into the mechanisms of sodium fluoride-induced developmental toxicity.

Fluoride exposure has a detrimental effect on neurodevelopment, while the underlying processes remain unknown. The goal of this study was to investigate how fluoride impacts synaptogenesis, with a focus on the phosphorylation of Creb1 (p-Creb1)-brain-derived neurotrophic factor (BDNF)-tyrosine kinase B (TrkB) pathway. We generated a sodium fluoride (NaF) model using C57 BL/6 J mice exposed to 100 mg/L NaF from gestation day 1 (GD1) to GD20. It was identified that NaF treatment impaired the learning and memory abilities of the male offspring, reduced dendritic spine density, lowered postsynaptic density protein-95 (PSD95) and synaptophysin (SYN) expression in the male offspring’s hippocampus, indicating that synaptic dysfunction may contribute to the cognitive impairment in the NaF model. In addition, in vivo experiment demonstrated that the protein abundance of BDNF and the ratio of p-Creb1 to Creb1 were increased in the hippocampus of NaF offspring, while the level of TrkB was reduced. Similarly, PC12 cells treated with NaF also showed increased expression of BDNF and decreased levels of TrkB. Notably, fluoride treatment increased p-Creb1 in vitro, while inhibiting p-Creb1 by 66615 significantly alleviated the effects of NaF exposure, indicating that p-Creb1 exerts a regulatory function in the BDNF-TrkB pathway. Altogether, these results demonstrated prenatal fluoride exposure triggered neurotoxicity in the male offspring hippocampus was linked to synaptogenesis damage caused by activating p-Creb1, which disrupted the BDNF-TrkB pathway.

Graphical abstract


Synaptic damage contributes to prenatal fluoride exposure induced cognitive dysfunction via disruption of the BDNF-TrkB axis, which is mediated by p-Creb1 signaling. Prenatal NaF exposure activated p-Creb1 and disrupted the BDNF-TrkB axis, leading to increased pro-BDNF accumulation and reduced TrkB protein abundance, as well as synaptogenesis failure and cognitive impairment. By reducing p-Creb1 with 66615, prenatal fluoride exposure induced BDNF-TrkB signaling was considerably inhibited.


Supplemental Figure 1. Effects of prenatal NaF exposure on other behaviors in male offspring mice. The rotarod fatigue test (A, B), open field test (C, D), elevated plus maze test (E), tail suspension…

*Full-text study online at https://www.sciencedirect.com/science/article/pii/S014765132200522X?via%3Dihub




Conte et al., 2020

G. Conte, A. Parras, M. Alves, I. Olla, L. De Diego-Garcia, E. Beamer, et al.

High concordance between hippocampal transcriptome of the mouse intra-amygdala kainic acid model and human temporal lobe epilepsy
Epilepsia, 61 (12) (2020), pp. 2795-2810, 10.1111/epi.16714

Darchen et al., 2016

A. Darchen, V. Sivasankar, M. Prabhakaran, et al.

Health effects of direct or indirect fluoride ingestion[M]//Surface Modified Carbons as Scavengers for Fluoride from Water
Springer, Cham (2016), pp. 33-62, 10.1007/978-3-319-40686-2_3

Esvald et al., 2020

E.E. Esvald, J. Tuvikene, A. Sirp, S. Patil, C.R. Bramham, T. Timmusk

CREB Family Transcription Factors Are Major Mediators of BDNF Transcriptional Autoregulation in Cortical Neurons
J. Neurosci., 40 (7) (2020), pp. 1405-1426, 10.1523/JNEUROSCI.0367-19.2019

Feng et al., 2020

F. Feng, Y. Jia, Y. Yang, H. Huan, X. Lian, X. Xu, et al.

Hydrogeochemical and statistical analysis of high fluoride groundwater in northern China
Environ. Sci. Pollut. Res. Int., 27 (28) (2020), pp. 34840-34861, 10.1007/s11356-020-09784-z

Flace et al., 2010

P. Flace, V. Benagiano, D. Vermesan, R. Sabatini, A.M. Inchingolo, P. Auteri, et al.

Effects of developmental fluoride exposure on rat ultrasonic vocalization, acoustic startle reflex and pre-pulse inhibition
Eur. Rev. Med. Pharmacol. Sci., 14 (6) (2010), pp. 507-512

Grandjean, 2019

P. Grandjean

Developmental fluoride neurotoxicity: an updated review
Environ. Health, 18 (1) (2019), p. 110, 10.1186/s12940-019-0551-x

Green et al., 2019

R. Green, B. Lanphear, R. Hornung, D. Flora, E.A. Martinez-Mier, R. Neufeld, et al.

Association between maternal fluoride exposure during pregnancy and IQ scores in offspring in Canada
Jama Pediatrics, 173 (10) (2019), pp. 940-948, 10.1001/jamapediatrics.2019.1729

Guth et al., 2020

S. Guth, S. Huser, A. Roth, G. Degen, P. Diel, K. Edlund, et al.

Toxicity of fluoride: critical evaluation of evidence for human developmental neurotoxicity in epidemiological studies, animal experiments and in vitro analyses
Arch. Toxicol., 94 (5) (2020), pp. 1375-1415, 10.1007/s00204-020-02725-2

Jiang et al., 2014

C. Jiang, S. Zhang, H. Liu, Z. Guan, Q. Zeng, C. Zhang, et al.

Low glucose utilization and neurodegenerative changes caused by sodium fluoride exposure in rat’s developmental brain
Neuromolecular Med., 16 (1) (2014), pp. 94-105, 10.1007/s12017-013-8260-z

Kowianski et al., 2018

P. Kowianski, G. Lietzau, E. Czuba, M. Waskow, A. Steliga, J. Morys

BDNF: a key factor with multipotent impact on brain signaling and synaptic plasticity
Cell Mol. Neurobiol., 38 (3) (2018), pp. 579-593, 10.1007/s10571-017-0510-4

Kraeuter et al., 2019

A.K. Kraeuter, P.C. Guest, Z. Sarnyai

The elevated plus maze test for measuring anxiety-like behavior in rodents
Methods Mol. Biol., 1916 (2019), pp. 69-74, 10.1007/978-1-4939-8994-2_4

Lepeta et al., 2016

K. Lepeta, M.V. Lourenco, B.C. Schweitzer, P.V. Martino Adami, P. Banerjee, S. Catuara-Solarz, et al.

Synaptopathies: synaptic dysfunction in neurological disorders – A review from students to students
J. Neurochem., 138 (6) (2016), pp. 785-805, 10.1111/jnc.13713

Li et al., 2016

C. Li, Y. Yan, J. Cheng, G. Xiao, J. Gu, L. Zhang, et al.

Toll-like receptor 4 deficiency causes reduced exploratory behavior in mice under approach-avoidance conflict
Neurosci. Bull., 32 (2) (2016), pp. 127-136, 10.1007/s12264-016-0015-z

Miranda et al., 2019

M. Miranda, J.F. Morici, M.B. Zanoni, P. Bekinschtein

Brain-derived neurotrophic factor: a key molecule for memory in the healthy and the pathological brain
Front. Cell Neurosci., 13 (2019), p. 363, 10.3389/fncel.2019.00363

Mridha et al., 2021

D. Mridha, P. Priyadarshni, K. Bhaskar, A. Gaurav, A. De, A. Das, et al.

Fluoride exposure and its potential health risk assessment in drinking water and staple food in the population from fluoride endemic regions of Bihar, India
Groundwater Sustain. Dev., 13 (2021), Article 100558

Murphy and Segal, 1997

D.D. Murphy, M. Segal

Morphological plasticity of dendritic spines in central neurons is mediated by activation of cAMP response element binding protein
Proc, Natl. Acad. Sci. U. S. A., 94 (4) (1997), pp. 1482-1487, 10.1073/pnas.94.4.1482

Qiu et al., 2020

L.L. Qiu, W. Pan, D. Luo, G.F. Zhang, Z.Q. Zhou, X.Y. Sun, et al.

Dysregulation of BDNF/TrkB signaling mediated by NMDAR/Ca(2+)/calpain might contribute to postoperative cognitive dysfunction in aging mice
J. Neuroinflammation., 17 (1) (2020), p. 23, 10.1186/s12974-019-1695-x

Rasool et al., 2018

A. Rasool, A. Farooqi, T. Xiao, W. Ali, S. Noor, O. Abiola, et al.

A review of global outlook on fluoride contamination in groundwater with prominence on the Pakistan current situation
Environ. Geochem Health, 40 (4) (2018), pp. 1265-1281, 10.1007/s10653-017-0054-z

Sakamoto et al., 2011

K. Sakamoto, K. Karelina, K. Obrietan

CREB: a multifaceted regulator of neuronal plasticity and protection
J. Neurochem., 116 (1) (2011), pp. 1-9, 10.1111/j.1471-4159.2010.07080.x

Serra et al., 2022

M.P. Serra, M. Boi, A. Carta, E. Murru, G. Carta, S. Banni, et al.

Anti-Inflammatory Effect of Beta-Caryophyllene Mediated by the Involvement of TRPV1, BDNF and trkB in the Rat Cerebral Cortex after Hypoperfusion/Reperfusion
Int. J. Mol. Sci., 23 (7) (2022), 10.3390/ijms23073633

Steiner et al., 2008

P. Steiner, M.J. Higley, W. Xu, B.L. Czervionke, R.C. Malenka, B.L. Sabatini

Destabilization of the postsynaptic density by PSD-95 serine 73 phosphorylation inhibits spine growth and synaptic plasticity
Neuron, 60 (5) (2008), pp. 788-802, 10.1016/j.neuron.2008.10.014

Strunecka and Strunecky, 2019

A. Strunecka, O. Strunecky

Chronic fluoride exposure and the risk of autism spectrum disorder
Int. J. Environ. Res. Public Health, 16 (18) (2019), p. 3431, 10.3390/ijerph16183431

Wang et al., 2022

Z.J. Wang, T. Shwani, J. Liu, P. Zhong, F. Yang, K. Schatz, et al.

Molecular and cellular mechanisms for differential effects of chronic social isolation stress in males and females
Mol. Psychiatry (2022), pp. 1-13, 10.1038/s41380-022-01574-y

Wen et al., 2022

J. Wen, Y. Xu, Z. Yu, Y. Zhou, W. Wang, J. Yang, et al.

The cAMP Response Element- Binding Protein/Brain-Derived Neurotrophic Factor Pathway in Anterior Cingulate Cortex Regulates Neuropathic Pain and Anxiodepression Like Behaviors in Rats
Front. Mol. Neurosci., 15 (2022), Article 831151, 10.3389/fnmol.2022.831151

Wu et al., 2020

Y. Wu, M. Wang, Y. Wang, H. Yang, H. Qi, B.J. Seicol, et al.

A neuronal wiring platform through microridges for rationally engineered neural circuits
APL Bioeng., 4 (4) (2020), Article 046106, 10.1063/5.0025921

Yoshii and Constantine-Paton, 2010

A. Yoshii, M. Constantine-Paton

Postsynaptic BDNF-TrkB signaling in synapse maturation, plasticity, and disease
Dev. Neurobiol., 70 (5) (2010), pp. 304-322, 10.1002/dneu.20765

Zhang et al., 2017

B. Zhang, X. Huo, L. Xu, Z. Cheng, X. Cong, X. Lu, et al.

Elevated lead levels from e-waste exposure are linked to decreased olfactory memory in children
Environ. Pollut., 231 (Pt1) (2017), pp. 1112-1121, 10.1016/j.envpol.2017.07.015

Further reading

Cao et al., 2016

J. Cao, Y. Chen, J. Chen, H. Yan, M. Li, J. Wang

Fluoride exposure changed the structure and the expressions of Y chromosome related genes in testes of mice
Chemosphere, 161 (2016), pp. 292-299, 10.1016/j.chemosphere.2016.06.106
Chakrabarty and Sarma, 2012

S. Chakrabarty, H. Sarma

Defluoridation of contaminated drinking water using neem charcoal adsorbent: kinetics and equilibrium studies
Int. J. ChemTech Res., 4 (2) (2012), pp. 511-516
DenBesten and Li, 2011

P. DenBesten, W. Li

Chronic fluoride toxicity: dental fluorosis
Monogr. Oral. Sci., 22 (2011), pp. 81-96, 10.1159/000327028
Fu et al., 2022

R. Fu, R. Niu, F. Zhao, J. Wang, Q. Cao, Y. Yu, et al.

Exercise alleviated intestinal damage and microbial disturbances in mice exposed to fluoride
Chemosphere, 288 (Pt 3) (2022), Article 132658, 10.1016/j.chemosphere.2021.132658
Lyaruu et al., 2008

D.M. Lyaruu, A.L. Bronckers, F. Santos, R. Mathias, P. DenBesten

The effect of fluoride on enamel and dentin formation in the uremic rat incisor
Pediatr. Nephrol., 23 (11) (2008), pp. 1973-1979, 10.1007/s00467-008-0890-2
Wang et al., 2021

D.M. Wang, L.Y. Cao, S.J. Pan, G. Wang, L.W. Wang, N.Y. Cao, et al.

Sirt3-mediated mitochondrial dysfunction is involved in fluoride-induced cognitive deficits
Food Chem. Toxicol., 158 (2021), Article 112665, 10.1016/j.fct.2021.112665
Wen et al., 2013

D.G. Wen, F.C. Zhang, E.Y. Zhang, C. Wang, S.B. Han, Y. Zheng

Arsenic, fluoride and iodine in groundwater of China
J. Geochem. Explor., 135 (2013), pp. 1-21, 10.1016/j.gexplo.2013.10.012
Wiatrak et al., 2020

B. Wiatrak, A. Kubis-Kubiak, A. Piwowar, E. Barg

PC12 cell line: cell types, coating of culture vessels, differentiation and other culture conditions
Cells, 9 (4) (2020), p. 958, 10.3390/cells9040958
Zhou et al., 2021

G. Zhou, Y. Hu, A. Wang, M. Guo, Y. Du, Y. Gong, et al.

Fluoride stimulates anxiety- and depression-like behaviors associated with SIK2-CRTC1 signaling dysfunction
J. Agric Food Chem., 69 (45) (2021), pp. 13618-13627, 10.1021/acs.jafc.1c04907
Zhou et al., 2021

L. Zhou, X. Tao, G. Pang, M. Mu, Q. Sun, F. Liu, et al.

Maternal nicotine exposure alters hippocampal microglia polarization and promotes anti-inflammatory signaling in juvenile offspring in mice
Front. Pharmacol., 12 (2021), Article 661304, 10.3389/fphar.2021.661304