模拟失重条件下骨形态发生蛋白-2诱导的成骨细胞蛋白激酶MEK1活性的变化

目的观察模拟失重条件下由骨形态发生蛋白-2（BMP-2）诱导的大鼠骨肉瘤成骨样细胞（ROS17／2．8）中丝裂原激活的蛋白激酶／细胞外信号调节激酶的激酶1（MAPK／ERK kinase1，MEK1）活性的变化。方法在地面1G和回转器模拟失重条件下培养ROS17／2．8细胞，培养时间分别为24h、48h和72h。培养结束前1h加入BMP-2（500ng／ml），1h后提取细胞蛋白，应用Western Blotting法检测细胞中的总细胞外信号调节激酶1／2（总ERK1／2）和磷酸化细胞外信号调节激酶（p-ERK1／2）的含量。另设一空白对照组，即1G条件下不加BMP-2的培养组。结果7个实验组细胞的总ERK1／2蛋白表达量无明显差异；空白对照组p-ERK1／2的表达量极低，明显低于其他6组（P〈0．01）；各时间点模拟失重组p-ERK1／2表达量均低于1G对照组（P〈0．01）；随着失重时间延长p-ERK1／2表达量呈逐渐降低的趋势（P〈0．01）。结论模拟失重条件下BMP-2诱导的成骨细胞MAPK信号通路中蛋白激酶MEK1的活性下降。

Effects of simulated weightlessness on the kinase activity of MEK1 induced by bone morphogenetic protein-2 in rat osteosarcoma cells

Objective To investigate the effects of simulated weightlessness on the activity of MAPK/ERK kinase 1(MEK1) induced by bone morphogenetic protein-2 (BMP-2) in rat osteosarcoma cells (ROS17/2.8). Methods Three experimental groups of ROS17/2.8 cells were cultured in rotating clinostat for 24 h, 48 h and 72 h respectively, 1 h before the end of culture, BMP-2 (500 ng/ml) was added into the medium, and the expression of total ERK1/2 and phosphated-ERK1/2 (p-ERK1/2) were detected by Western Blotting method at the end of culture. Three control groups cultured under 1 G condition, and a blank control group without adding BMP were set. Results For expression of total ERK1/2, there were no significant differences among all seven groups. The expression of p-ERK1/2 was unconspicuous in the blank control group significantly lower than that in other six groups(P<0.01). The levels of p-ERK1/2 in simulated weightlessness groups were significantly than that in 1 G group in every time point(P<0.01). The expression of p-ERK1/2 decreased along with the duration of weightlessness simulation(P<0.01). Conclusion The kinase activity of MEK1 induced by BMP-2 in rat osteosarcoma cells was lowered under simulated weightlessness.