BACKGROUND: Due to their good differentiation abilities, human periodontal ligament stem cells (hPDLSCs) and tissue engineering treatment modalities are used to treat bone defects due to periodontitis. This in-vitro study aimed to determine the effects of different melatonin concentrations on the viability of cultured periodontal ligament stem cells.

MATERIAL AND METHODS: Cultured hPLDSCs were treated with different melatonin concentrations. The study groups were divided into 9 concentration-based groups: Group 1, untreated hPDLSCs; Group 2, hPDLSCs exposed to physiological doses of melatonin (1 μM); Group 3, hPDLSCs exposed to 10 μM melatonin; Group 4, hPDLSCs exposed to 20 μM melatonin; Group 5, hPDLSCs exposed to 30 μM melatonin; Group 6, hPDLSCs exposed to 40 μM melatonin; Group 7, hPDLSCs exposed to 50 μM melatonin; Group 8, hPDLSCs exposed to 100 μM melatonin; Group 9, hPDLSCs exposed to 150 μM melatonin. Cell viability was evaluated at 14 and 21 days using the AlamarBlue (AB) Cell Viability Assay, a toxicity assay.

RESULTS: Melatonin had a positive effect on hPDLSC viability in all test groups. A general pattern of decreasing cell viability with increasing melatonin concentrations was observed, with Groups 8 and 9 showing the lowest viability. An abrupt pattern was detected in Groups 4 and 7, where a sudden, significant increase in cell viability was observed, in contrast with the general observed pattern.

CONCLUSIONS: In conclusion, the hPDLSCs remained viable when exposed to the melatonin doses used, under osteogenic media, except for the 100µM and 150 µM melatonin groups. Therefore, further studies are required with hPDLSCs exposed to different concentrations of melatonin.

Keywords: Melatonin, Osteogenesis, Periodontal Ligament, Stem Cells, Tissue Survival, Stem Cells, Severe Combined Immunodeficiency, Humans, Cell Survival, Cells, Cultured, Cell Differentiation, Tissue Engineering