Fluoride Action Network

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Abstract

Fluoride, a geochemical element, can damage the brain and result in dysfunction of the central nervous system. In recent years, fluoride-induced neurotoxicity has become one of research focuses of environmental toxicology. Our previous study showed that fluoride could induce the structural damages of the cerebral cortex and reduce the learning and memory abilities of mice offspring. However, the underlying mechanisms of these effects remain unclear. In this study, primary neurons were isolated from the cerebral cortices of postnatal 1-day SD rats. The primary cultured cerebral cortical neurons were adherent and the cellular network was obvious. Neurons were identified by Nissl’s staining and were used for experiments. Different concentrations of sodium fluoride (0.5, 1.0, 1.5, 2.0 and 2.5 mM) were chosen to explore its toxic effects on neuron of SD rats in vitro. Results showed that neuronal morphology was obviously damaged in 2.0 and 2.5 mM, but was not adversely affected in 0.5 and 1 mM. Further studies revealed that the neurites of neuron were shrunken and even became fractured with the increase in NaF dose, which have been detected by scanning electron microscopy (SEM). Meanwhile, TEM showed marginated chromatin, widened nuclear gaps, damaged nuclei and swollen or even absent mitochondria in 1.5, 2 and 2.5 mM group. The cytoskeletal staining was consistent with the above results. The number of neurites of cerebral cortical neuron significantly decreased after fluoride exposure by immunofluorescent assay. In summary, high fluoride (1.5, 2 and 2.5 mM) concentrations exerted a significant toxic effect on the cellular morphologies and neural formation of primary cultured cortical neurons. These findings provide new insights into the roles of NaF in neuronal damage and can contribute to an improved understanding of fluoride-induced neurotoxicity.

*Original abstract online at https://link.springer.com/article/10.1007%2Fs11356-021-13950-2

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Funding

This work was supported by the National Natural Science Foundation of China (No. 32002352), Scientific and Technological Foundation of Henan Province in China (202102310629, 202300410165, 192102110080) and the China Postdoctoral Science Foundation (Grant No. 2019M652548).

Author information

Affiliations

College of Animal Science and Veterinary Medicine, Henan Institute of Science and Technology, Xinxiang, China

Hongmei Ning, Chong Li, Zhihong Yin, Dongfang Hu, Yaming Ge & Lingli Chen

*Original abstract online at https://link.springer.com/article/10.1007%2Fs11356-021-13950-2