Melatonin Influences the Proliferative and Differentiative Activity of Rat Adipose-Derived Stem Cells

Objective: This study was performed to determine whether melatonin atphysiological concentrations (0.01-10nM) could affect the proliferation andosteogenic differentiation of Rat ADSCs in vitro.Materials and Methods: ADSCs were isolated from the fat of adult rats. Aftercell expansion in culture media and through three passages, osteogenesiswas induced on a monolayer culture with osteogenic medium with or withoutmelatonin at physiological concentrations (0.01-10nM). After 4 weeks cultureswere examined for mineralization by Alizarin Red S and von Kossa staining andfor alkaline phosphatase (ALP) activity by ALP kit. Cell viability and apoptosiswere also assayed by 3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-ulfophenyl)-2H-tetrazolium assay and flowcytometry, respectively. Allassays were performed in triplicate.Results: The results indicated that at physiological concentrations, melatoninsuppressed proliferation and differentiation of ADSCs. These data indicate thatADSCs exposed to melatonin, had a lower ALP activity in contrast to the cellsexposed to the osteogenic medium alone. Similarly, the mineral deposition(calcium level) also decreased. The flow cytometry proved that the cell growthdecreased and the apoptotic cells increased.Conclusion: These results suggest that physiological concentration ofmelatonin has a negative effect on ADSCs osteogenesis.