title: Effects of melatonin on the proliferation and differentiation of rat adipose-derived stem cells.
abstract: BACKGROUND
  Osteogenesis driven by adipose-derived stem cells (ADSCs) is regulated by physiological and pathological factors. Accumulating evidence from in vitro and in vivo experiments suggests that melatonin may have an influence on bone formation. However, little is known about the effects of melatonin on osteogenesis, which thus remains to be elucidated. This study was performed to determine whether melatonin at physiological concentrations (0.01-10 nM) could affect the in vitro proliferation and osteogenic differentiation of rat ADSCs.
  
  
  METHODS
  ADSCs were isolated from the fat of adult rats. After cell expansion in culture media and through three passages, osteogenesis was induced in a monolayer culture using osteogenic medium with or without melatonin at physiological concentrations (0.01-10 nM). After four weeks, the cultures were examined for mineralization by Alizarin Red S and von Kossa staining and for alkaline phosphatase (ALP) activity using an ALP kit. Cell viability and apoptosis were also assayed by 3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTT) assay and flow cytometry, respectively.
  
  
  RESULTS
  The results indicated that at physiological concentrations, melatonin suppressed proliferation and differentiation of ADSCs. These data indicate that ADSCs exposed to melatonin, had a lower ALP activity in contrast to the cells exposed to osteogenic medium alone. Similarly, mineral deposition (calcium level) also decreased in the presence of melatonin. Flow cytometry confirmed that cell growth had decreased and that the numbers of apoptotic cells had increased.
  
  
  CONCLUSIONS
  These results suggest that the physiological concentration of melatonin has a negative effect on ADSC osteogenesis.
authors.forename: Arash
authors.initials: A
authors.lastname: Zaminy
authors.forename: Iraj Ragerdi
authors.initials: IR
authors.lastname: Kashani
authors.forename: Mohammad
authors.initials: M
authors.lastname: Barbarestani
authors.forename: Azim
authors.initials: A
authors.lastname: Hedayatpour
authors.forename: Reza
authors.initials: R
authors.lastname: Mahmoudi
authors.forename: Safoura
authors.initials: S
authors.lastname: Vardasbi
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Shokrgozar