急性有氧运动对大鼠海马组织PI3K/Akt/GSK3β信号通路的影响
Effects of Acute Aerobic Exercise on PI3K/Akt/GSK3β Pathway of Hippocampus in Rats

摘要：目的：探讨急性有氧运动对大鼠海马组织PI3K/Akt/GSK3β信号通路的影响。方法：雄性SD大鼠随机分为安静对照组（CG）和急性运动组（EG）。EG组大鼠进行1 h急性有氧运动，跑台速度为25 m/min，相当于75% VO2max负荷强度。运动后即刻、12 h、24 h、36 h和48 h，分离海马组织，通过荧光定量PCR和Western blot检测PI3K催化亚基p110、Akt、GSK3β以及下游底物tau的mRNA和蛋白含量及其磷酸化水平。结果：急性有氧运动后EG组大鼠海马组织PI3K p110 mRNA和蛋白含量均呈现先上升后下降的趋势；12 h时mRNA含量达到最高，约是CG组的2.21倍（P<0.01）；而24 h时其蛋白含量达到最高，约是CG组的1.45倍（P<0.05）；至48 h时其mRNA和蛋白含量均下降至CG组水平。Akt和GSK3β的mRNA和总蛋白含量在48 h内与CG组相比无显著性变化；而Akt Ser473位和GSK3β Ser9位的磷酸化水平在24 h时均达到最高峰，分别是CG组的5.98倍（P<0.01）和2.4倍（P<0.01）；48 h时逐渐下降至CG组水平。下游底物tau的磷酸化水平却呈现先下降后上升的趋势，在24 h时其Ser202位磷酸化水平最低，约为CG组的60%（P<0.05）。结论：急性有氧运动能够在短期内提高大鼠海马组织PI3K p110 mRNA和蛋白含量，增强其激酶活性；提高Akt Ser473位磷酸化水平，激活Akt；活化的Akt使GSK3β Ser9位磷酸化水平提高，抑制GSK3β的激酶活性；最终导致tau蛋白Ser202位的磷酸化水平降低。因此急性有氧运动能够在短期内提高大鼠海马组织PI3K/Akt/GSK3β信号通路活性。
Abstract: Objective: To investigate the effects of acute aerobic exercise on PI3K/Akt/GSK3β pathway of hippocampus in rats. Methods: Sprague-Dawley rats were randomly assigned to two groups: control group (CG) and acute exercise group (EG). The rats of EG group underwent 1 h treadmill running at the speed of 25 m/min (75% VO2max). Then the hippocampus was isolated at 0 h, 12 h, 24 h, 36 h and 48 h after exercise. The mRNA and protein and phosphorylation levels of PI3K catalytic subunit p110, Akt, GSK3β and tau were analyzed by quantitative PCR or Western blot. Results: After acute aerobic exercise, mRNA and protein levels of PI3K p110 in the EG group increased firstly and then declined. PI3K p110 mRNA level in EG group reached the maximum at 12 h that were 2.2-fold higher than it in CG group (P < 0.01), and its protein level was 1.45-fold higher than that in CG group at 24 h after exercise (P < 0.05). At 48 h after exercise, there were no differences in mRNA and protein levels of PI3K p110 between EG and CG groups. Compared with CG group, the mRNA and protein expressions of Akt and GSK3β didn’t change at 48 h after exercise, but the phosphorylation levels of Akt Ser473 and GSK3β Ser9 were highest at 24 h after exercise, they were 5.98-fold and 2.4-fold higher than those in the CG group respectively (P < 0.01), and they were decreased to the level of CG group at 48 h after exercise. The phosphorylation levels of tau Ser202 decreased at first and then increased, and it was lowest at 24 h after exercise, it was about 60% of that in CG group (P < 0.05). Conclusions: Acute aerobic exercise can improve the mRNA and protein expressions of PI3K p110 and its kinase activity of rats’ hippocampus in a short time, and enhance the phosphorylation levels of Akt Ser473 and active the