Effects of L-Arg, L-Cit and LALC on senescence in HUVECs.

<p>Cells were incubated with 5.5 mM glucose (NG) or 22 mM glucose (HG) for 3 days in the absence and presence of L-Arg (300 μM), L-Cit (300 μM) or LALC (150 μM each of L-Arg and L-Cit). (A) SA-ß-gal activity was measured to evaluate cellular senescence by flow cytometry (n = 5). (B) Representative photographs of SA-ß-gal staining (<i>blue;</i> SA-ß-gal positive cells). (C) Cellular growth curves determined by the counting dye method. All measures were performed in triplicate. (D) Telomerase activity was measured using the TRAP assay (n = 3). (E, F) The effect of L-Arg and/or L-Cit on DNA damage (as measured by the apurinic/apyrimidinic (AP) sites) (n = 4) (E) and a molecular marker of senescence (p16^INKa protein) (n = 3) (F). ##P<0.01, #P<0.05 versus NG. **P<0.01, *P<0.05 versus HG. Data are given as the mean ± SD from at least three independent experiments.