Cytogenetic effects of fluoride on human lymphocytes in vitro

Abstract

Fluoridation of the communal water supply, the topical application of fluoride to the tooth surface, and fluoride mouth-rinsing for the purpose of the prevention of dental caries have been widely practiced in many countries in the world. In spite of the world-wide use of fluoride for the dental caries prevention, it is still unknown whether or not fluoride has mutagenic and carcinogenic effects.In the present study, the effect of fluoride on human chromosomes was examined. The main purpose of this investigation was to analyse the dose-response relationship between NaF and the frequency of chromosomal aberrations by employing a low dose of NaF.Using the peripheral blood from nine healthy men, aged from 24 to 29 years, a human lymphocyte culture was made for 72 hours. NaF was added to the medium 24 hours before the termination of culture.Doses of NaF employed in the present study were 0, 1, 2, 4, 8, and 16 ppm at the final concentrations in the medium. Three hundred metaphase plates with good quality were examined for each NaF dose in every blood sample. The numbers of the structural and numerical chromosome anomalies and mitotic indices were scored for each dose group and then compared statistically one another.The results obtained were as follows:1. It was found that NaF was anti-mutagenic rather than mutagenic at the dose level of 1 ppm in terms of suppressing the occurrence of structural chromosome anomalies.2. In the range of 0 to 16ppm of NaF, the maximum frequency of abnormal cells was found at 8ppm. The frequency was about 10%, that was about 1.5 times as high as the value of the control (0 ppm of NaF).3. Frequencies of other parameters of anomalies such as the mitotic index and the distribution of structural anomalies in the NaF groups were not particularly different from those of the control.