Objective: To investigate the effect of p38 mitogen-activated protein kinase (MAPK) gene knockout on the proliferation of embryonic fibroblasts in mice (MEFs).
Methods: The expression of p38 in MEFs p38+/+ and p38(-/-) cells were detected by Western blotting. The growth curves of p38+/+ and p38(-/-) cells were plotted with the results of methylthiazoletetrazolium (MTT) colorimetric assay, and the ratios of different cell phases of p38+/+ and p38(-/-) cells were analyzed by flow cytometry.
Results: The growth curves showed that the growth rate was notably retarded and cell double time elongated in p38(-/-) cells, and there was 15.5% decrease of the number of p38(-/-) cells in comparison with that of p38+/+ cells in 96-hour culture. G2/M transition was inhibited in p38(-/-) cells. Meanwhile, G1/S transition was also inhibited in p38(-/-) cells, as shown by the results of flow cytometry. The ratios of G0/G1, G2/M, and S phases of p38+/+ cells were 34.47%, 10.81%, and 54.72%, respectively; while those of p38(-/-) cells were 48.49%, 4.06%, and 47.44%, respectively. There were 40.7% increase and 13.3% decrease in the cell numbers of G1 and S phases of p38(-/-) cells in comparison with those of p38+/+ cells, respectively.
Conclusion: p38 gene knockout in MEFs leads to cell cycle arrest and decreased cell proliferation.