Decreased longevity of human diploid cells after incorporation of latex spheres within their cytoplasm

The effects of cytoplasmic incorporation of latex spheres (a cytoplasmic marker) on the growth potential of human diploid cells was examined. After incorporation of latex spheres within their cytoplasm, GM2290 (diploid, Lesch-Nyhan) cells showed a reduced replicative potential. A lower percentage of cells exposed to latex particles incorporated [³H]thymidme during any subsequent 24-h test period when compared with comparable, untreated cells. The overall life expectancy of the cultures treated with spheres was reduced approx. 25%. A similarly treated and examined transformed cell line (HeLa) showed no similar adverse effects after incorporation of latex spheres. The results suggest that latex spheres should be used with caution in experiments on in vitro cellular senescence.