模拟失重对成骨细胞整合素亚单位表达的影响

Effects of simulated weightlessness on expression of integrin subunits in osteoblasts

目的:观察回转器模拟失重对成骨细胞整合素亚单位表达的影响.方法:培养的大鼠乳鼠颅骨成骨随机分为对照组和失重组(用回转器模拟失重条件),在实验的24,48和72h提取细胞总RNA,进行反转录PCR,检测整合素的α5,αv和β1亚单位mRNA表达,并计算与内参照β肌动蛋白(beta-actin)mRNA水平的比值.同时用Westernblotting检测各种整合素亚单位的蛋白表达变化.结果:从模拟失重24h开始,整合素亚单位的基因表达即发生改变,但在对照组中,基因表达无明显变化.整合素α5mRNA在模拟失重的24,48和72h分别下降了11.3%,18.7%和9.8%;整合素αvmR-NA分别下降了23.0%,12.3%和16.7%;整合素β1mRNA分别下降了15.3%,11.4%和26.4%.与对照组相比差异均有统计学意义(P<0.05).整合素亚单位蛋白和基因表达的变化相似.整合素α5在模拟失重的24,48和72h分别下降了13.1%,20.3%和11.9%;整合素αv的蛋白表达分别下降了7.4%,18.2%和25.2%;整合素β1蛋白表达分别下降了18.6%,25.9%和27.5%.与对照组相比差异均有统计学意义(P<0.05).结论:在模拟失重环境下,整合素α5,αv和β亚单位mRNA的表达发生了下调性变化.

AIM： To investigate the expression of integrin subunits in osteoblasts during simulated weightlessness induced by clinostat. METHODS ： Calvarial osteoblasts of neonate rats were cultured under conditions of normal gravity（1G） and simulated weightlessness induced by clinostat respectively. The total RNA in cells was isolated in different time points （24, 48, 72 h）. Reverse transcription PCR analysis was made to examine the gene expression of α5, or, and β1 integrin subunits. Each value was normalized against that of β-actin mRNA. Moreover, the protein expressions of all kinds of integrin subunits were also detected with Western blotting. RESULTS： The gene expression of 3 integrin subunits started to change from 24 h of rotation in clinostat but not in stationary cultures. The expression of integrin α5 mRNA decreased at 24, 48 and 72 h of rotation by 11.3%, 18.7% and 9.8%, respectively. The same trend was saw in the expression of integrin or, mRNA as 23.0% , 12.3% and 16.7%, respectively. Moreover, the expressions of integrin β1 mRNA in different periods were also declined by 15.3% , 11.4% and 26.4% , respectively. The differences were all statistically significant as compared with controls （P 〈 0.05 ）. The protein expression of 3 integrin subunits also started to change from 24 h of rotation in clinostat. The expression of integrin α5 at 24, 48 and 72 h decreased by 13.1%, 20.3% and 11.9% , respectively. The same trend was seen in the expression of integrin αv as 7. 4%, 18. 2% and 25.2%, respectively. Moreover, the expressions of integrin 131 protein in different periods were also declined by 18.6%, 25.9% and 27.5%, respectively. The differences were all statistically significant as compared with controls （ P 〈 0.05 ）. CONCLUSION： The expressions of α5, αv, β1 integrin subunits decrease in simulated weightlessness.