低氧预适应鼠脑内核糖体S6激酶磷酸化水平和蛋白表达量的变化

CHANGES OF RSK PHOSPHORYLATION AND PROTEIN EXPRESSION LEVELS IN THE BRAIN OF HYPOXIC PRECONDITIONED MICE

探讨核糖体S6激酶(ribosomal S6kinase,RSK)Ser221(PDK1磷酸化位点)和Thr359/Ser363(ERK1/2磷酸化位点)的磷酸化水平以及总RSK蛋白表达量在小鼠脑低氧预适应发生发展过程中的变化。将成年雄性BALB/c小鼠(18～22g)随机分为正常对照(H0)和重复性低氧1～4次(H1～H4)等5组(每组n=6)。应用蛋白凝胶电泳(SDS-PAGE)和蛋白印迹(Western blot)技术,定量检测整体低氧预适应小鼠海马和皮层组织内Ser221位点(p-Ser221 RSK)和Thr359/Ser363位点(p-Thr359/Ser363 RSK)的磷酸化水平以及总RSK蛋白表达量。结果表明,随着低氧暴露次数增加,小鼠海马和皮层组织内p-Ser221 RSK磷酸化的水平显著增高(P<0.05,n=6),伴随着p-Thr359/Ser363 RSK磷酸化的水平明显降低(P<0.05,n=6);而RSK总蛋白的表达量则无明显改变。结果提示,Ser221 RSK磷酸化水平增高和Thr359/Ser363 RSK磷酸化水平降低可能参与了小鼠脑低氧预适应的发生发展过程。

To investigate the changes of protein expression and phosphorylation levels at Ser221 （PDK1 site） and Thr359/Ser363 （ERK1/2 sites） of ribosomal S6 kinase （RSK） in the brain of hypoxie preconditioned mice, adult male BALB/e mice （weighing 18 - 22g） were randomly divided into 5 groups （ at least n =6 for each group） as follows： normoxie control （H0） and repetitive hypoxie exposure groups （ H1 - H4）, respectively. The biochemical techniques of SDS-PAGE and Western blot were performed to detect the total RSK protein expression, and phosphorylation levels at Ser 221 （p-Ser221 RSK） and Thr359/Ser363 sites （p-Thr359/Ser363 RSK） of RSK both in hippocampus and cortex of mice. We found that the increased p-Ser221 RSK （ P 〈 0.05, n = 6 ） eompanied with significant decrease of p-Thr359/Ser363 RSK levels （P 〈0.05, n = 6） both in hippocampus and cortex of hypoxie preconditioned mice. However, there were no significant changes of total RSK protein expression in the brain of mice following repetitive hypoxie exposure （ H1 - H4, n = 6 for each group） comparing with that of H0 group. These results suggest that the increased p-Ser221 RSK and the down-regnlated p-Thr359/Ser363 RSK might be involved in the development of cerebral hypoxie preconditioning of mice.