Effect of 2-mercaptoethylamine on proliferation and lifespan of WI-38 cells

The antioxidant 2-mercaptoethylamine (MEA) was added to the culture medium of WI-38 cells throughout their lifespan. MEA concentrations of 0.5 microM, 5 microM and 50 microM were used. The presence of 5 microM or 50 microM MEA decreased the fraction of rapidly dividing cells and slightly reduced cell density at confluence, whereas 0.5 microM MEA had no significant effect on these parameters. All MEA-treated cultures had somewhat reduced plating efficiency. Cultures treated with 0.5 microM, 5 microM and 50 microM MEA attained population doubling levels of 72.80, 78.35 and 70.92, respectively, compared to 73.55 for untreated controls. Cells grown in 5 microM MEA underwent 4.8 more population doublings, in six weeks more time in culture, compared to controls. This is a 12.2% increase in the portion of the lifespan examined and a 6.5% increase in total lifespan. These results are consistent with the free radical theory of aging.