The inhibitory effect of Hcy on DNA synthesis is reversible in ECs.

HUVECs were exposed to dl-Hcy for 24 hours, then washed with PBS, and cultured with fresh control medium for the time indicated. [³H]-thymidine incorporation was measured at indicated times. The value of no Hcy treatment control for each time point was set as 100%, and [³H]-thymidine incorporation was divided by the control value. Values represent the mean ± SD of 3 separate experiments (n = 9). *P < .01 versus 0 hour sample in control medium after Hcy treatment.