TiF₄ and NaF present similar cytotoxic effect on NIH/3T3 fibroblast

Methods: NIH/3T3 Fibroblasts were cultured in Dulbecco’s Modified Eagle's Medium (DMEM) supplemented with 10% fetal bovine serum. Cultures were incubated at 37^oC in a humidified atmosphere of 5%CO_2. Cells were harvested by tripsinization and plated in 96-well microplates for the reduction of dimetiltiazol difenil Tetrazolium (MTT) assay. The cells at a density of 5 x 10³ were treated with DMEM containing NaF (0.34 to 5.42%, pH adjusted to 4.5 and natural pH 9.5) or TiF₄ (0.25 to 4%, pH adjusted to 4.5 and natural pH 1.0). Positive control consisted of DMEM without treatment. Cells at a density of 5 x 10⁴ were seeded in 24-well plates, fixed and stained with HE for the morphologic analysis (n=3). Furthermore, 4 x 10⁴ cells were seeded in 24-well plates, collected for counting total viable cells assay using Neubauer chamber and optical microscope (n=2). The experimental analyses were performed after 6, 12, 24 and 48h of treatment. MTT absorbance values were analysed and compared using Kruskall-Wallis and Dunn test (n=6, p<0.05).

Results: Generally, the absorbance values presented by the cells treated with the fluoride salts were closed to zero, while the absorbance of the control group varied from 0.2 to 0.6 according to the experimental period. There were no significant differences between the fluoride salts and concentrations in respect to the cell viability. The treatment with fluoride also promoted morphologic changes and reduction in cells number, regardless of the fluoride salt and concentration. For TiF₄, the cell morphology seemed to be more altered when the pH was adjusted.

Conclusion: Analysis of the results indicates that TiF₄ and NaF had similar effect towards the NIH/3T3 cell number, viability and morphology.