title: Effect of exogenous nitric oxide on the proliferation of a human osteoblast (HOS) cell line induced by hydroxyapatite.
abstract: OBJECTIVE
  The aim of this study was to test the hypothesis that the proliferation of hydroxyapatite (HA)-induced human osteoblast cell line (HOS cells) may be up-regulated by exogenous nitric oxide (NO).
  
  
  METHODS
  HOS cells were cultured on the surface of HA with or without the presence of a NO donor, S-nitroso acetyl penicillamine (SNAP) or nitroso acetyl penicillamine (NAP). 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) known as carboxy PTIO, a NO scavenger, was added in the cell cultures with or without the presence of SNAP. The cells were also pre-treated with L-N5-(1-iminoethyl)orthinine hydrochloride (L-NIO), an endothelial nitric oxide synthase (eNOS) inhibitor, or anti-integrin alphaV antibody before culturing on HA surfaces with or without the presence of SNAP. Medium, cells alone or cells pretreated with these inhibitors or antibodies was used as the controls. Cell proliferation was assessed by colorimetric assay.
  
  
  RESULTS
  The results showed that SNAP, but not NAP, augmented HA-induced HOS cell proliferation. This modulatory effect of SNAP on HA-induced HOS cell proliferation was abolished by carboxy PTIO or anti-integrin alphaV antibody, but only partially reduced by L-NIO.
  
  
  CONCLUSIONS
  Therefore, the results of this study suggest that exogenous NO alone may up-regulate the proliferation of HOS cells attached on HA surfaces via integrin alphaV molecules.
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Gadjah Mada University, Yogyakarta - Indonesia and School of Dental Sciences, University Sains Malaysia, Kota Bharu - Malaysia.
authors.forename: Erwan
authors.initials: E
authors.lastname: Sugiatno
authors.forename: Abdul R
authors.initials: AR
authors.lastname: Samsudin
authors.forename: Wihaskoro
authors.initials: W
authors.lastname: Sosroseno