Figure 3.

Protein expression of p16INK-4a in response to glucose stress. Expression of p16INK-4a increases with population doubling levels (PDLs) in human umbilical vein endothelial cells (HUVECs). Low and high glucose enhances upregulation of p16INK-4a protein expression in endothelial cells at PDL 25. HUVECs were incubated with each of the previously described glucose treatments at the indicated PDL time points. (a) Western blot analyses of p16INK-4a protein were performed with 20 μg of cell lysate. (b) Relative p16INK-4a protein expression was quantified by densitometric analysis associated with Licor Odyssey software (data are normalized against GAPDH and expressed as means ± SE). Data are presented as means ± SE in four experiments. *p < .05, significantly different from control HUVECs cultured in the absence of high glucose.