IADR Abstract Archives
Cellular Responses Of Fluoride-Resistant Fibroblasts To High Fluoride Concentrations
Objectives: Dental or bone fluorosis is caused by exposure to excessive fluoride intake. Yet there is a varying individual susceptibility to the same level of fluoride exposure across the population. The underlying mechanisms of fluoride resistance essential for understanding this diversity remain elusive. This study aimed to investigate the cellular response of fluoride-resistant mouse fibroblasts to media of high fluoride concentrations.
Methods: Fluoride-resistant (FR)-90 L-929 cells were developed from regular L-929 cells (ATCC CCL-1, Manassas, VA) by sequentially exposure to gradient ascending fluoride up to 90-ppm in culture media. The proliferation rate of the FR-90 L-929 cells and regular L-929 cells were determined using the MTT assay. The FR-90 L-929 cells were examined in the media of 90-ppm and compared with the regular L-929 cells using a highly specific fluorescent fluoride probe to trace the fluoride transportation. The fluoride distribution in cells was further investigated and compared.
Results: The FR-90 L-929 cells were able to grow in media of 90-ppm fluoride. There was no significant difference between the proliferation rates of FR-90 L-929 cells and regular L-929 cells, yet changes of FR-90 cell morphology were observed compared with the regular L-929 cells. By using fluoride probe at the non-cytotoxic dosage, sphered congregations of fluoride were detected in both the FR-90 and regular L-929 cells. In FR-90 L-929 cells the fluoride ions were restricted in endoplasmic reticulum region around nucleus whereas in regular L-929 cells the fluoride ions were distributed homogenously in cytoplasm.
Conclusions: Intracellular fluoride distribution differs between fluoride-resistant and regular L-929 cells, indicating that endoplasmic reticulum is possibly involved in fluoride resistance mechanisms.
Methods: Fluoride-resistant (FR)-90 L-929 cells were developed from regular L-929 cells (ATCC CCL-1, Manassas, VA) by sequentially exposure to gradient ascending fluoride up to 90-ppm in culture media. The proliferation rate of the FR-90 L-929 cells and regular L-929 cells were determined using the MTT assay. The FR-90 L-929 cells were examined in the media of 90-ppm and compared with the regular L-929 cells using a highly specific fluorescent fluoride probe to trace the fluoride transportation. The fluoride distribution in cells was further investigated and compared.
Results: The FR-90 L-929 cells were able to grow in media of 90-ppm fluoride. There was no significant difference between the proliferation rates of FR-90 L-929 cells and regular L-929 cells, yet changes of FR-90 cell morphology were observed compared with the regular L-929 cells. By using fluoride probe at the non-cytotoxic dosage, sphered congregations of fluoride were detected in both the FR-90 and regular L-929 cells. In FR-90 L-929 cells the fluoride ions were restricted in endoplasmic reticulum region around nucleus whereas in regular L-929 cells the fluoride ions were distributed homogenously in cytoplasm.
Conclusions: Intracellular fluoride distribution differs between fluoride-resistant and regular L-929 cells, indicating that endoplasmic reticulum is possibly involved in fluoride resistance mechanisms.