Figure 4.

Effects of rotation‐simulated microgravity and hypergravity on HL‐1 cell proliferation. A, Analysis of cell number following microgravity. B‐D, mRNA levels of PCNA, C‐fos and CyclinD1 were analysed by qPCR. E, Expression levels of mammalian target of rapamycin (mTOR), phosphorylated mTOR at Ser1248 (p‐mTOR) and PCNA in HL‐1 cells. F, Analysis of cell number following exposure to 4G hypergravity. G‐I, mRNA levels of PCNA, C‐fos and CyclinD1 were analysed after 4G centrifugation for 48 h. J, Expression of p‐mTOR and PCNA in HL‐1 cells treated with 4G hypergravity. Representative results of three independent experiments are shown. Data are shown as mean ± SEM; unpaired Student's t test, *P < .05 and **P < .01