Effects of hypergravity on adherent human cells.

In recent years, accumulating evidence has shown that microgravity or hypergravity may affect cell growth and differentiation. Since it is not easy to carry out researches in space or to simulate weightlessness on earth, we conducted experiments on simulated hypergravity (2 to 15 g) by using a centrifuge (radius: 80 cm; speed motor: 180 rpm). We looked for the effects of chronic hypergravity (7 to 10 days) on cultures of three human cell lines: lung or dermic fibroblasts and lung adenocarcinoma A 549 cells. The results showed a significant decrease (10-20%, P<0.05) in cell proliferation connected to a significant decrease (20-50%, P<0.01) in culture DNA content under hypergravity, but only for lung fibroblasts. The protein content was never disturbed. Dermic fibroblast elastase activity was enhanced (8-13%, P<0.02) under 15 g. Total phospholipid content as well as relative amounts of phospholipid components, analysed by thin layer chromatography, were unchanged in A 549 cells.