RT Journal Article SR Electronic T1 Changes in Fluoride Sensitivity During In Vitro Senescence of Normal Human Oral Cells JF Anticancer Research JO Anticancer Res FD International Institute of Anticancer Research SP 2085 OP 2090 VO 25 IS 3B A1 RIE SATOH A1 KAORI KISHINO A1 SUFI REZA MD. MORSHED A1 FUMITOSHI TAKAYAMA A1 SUMIKO OTSUKI A1 FUMIKA SUZUKI A1 KEN HASHIMOTO A1 HIROTAKA KIKUCHI A1 HIROFUMI NISHIKAWA A1 TOSHIKAZU YASUI A1 HIROSHI SAKAGAMI YR 2005 UL http://ar.iiarjournals.org/content/25/3B/2085.abstract AB We have previously reported that sodium fluoride (NaF) showed slightly higher cytotoxicity against human oral tumor cell lines than normal human oral cells. Possible changes in the NaF sensitivity of three normal human oral cell types (gingival fibroblast HGF, pulp cell HPC, periodontal ligament fibroblast HPLF) during in vitro ageing were investigated in the present study. When these cells were subcultured at 1:4 split ratio every week, their saturation density declined with increasing population doubling level (PDL), and they ceased to divide when they reached 20 PDL. Mitochondrial function, evaluated by MTT stainability per cell basis, was elevated at the terminal phase. NaF dose-dependently reduced the viable cell number, but did not show any beneficial (growth promoting) effect (so-called “hormesis”) at lower concentrations. NaF produced large DNA fragments, without induction of internucleosomal DNA fragmentation, possibly due to weak activation of caspases -3, -8 and -9. Higher concentrations of NaF were required to reduce the number of viable senescent cells than younger cells, indicating that cells become resistant to cytotoxicity of NaF with in vitro ageing. Copyright© 2005 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved