SOD1和 PI3K/AKT 信号转导通路在丙泊酚防治兔脊髓缺血-再灌注损伤中的作用

摘要

目的：探讨超氧化物歧化酶-1(SOD1)和磷脂酰肌醇3激酶(PI3K)/丝氨酸(苏氨酸)蛋白激酶 B(AKT)的信号转导通路在缺血前后丙泊酚联合运用防治兔脊髓缺血-再灌注损伤(SCIRI)中的作用。方法将60只日本大耳白兔(雄性)随机均分为3组(n=20)：假手术组(S 组)、缺血-再灌注组(I/ R 组)和丙泊酚保护组(P 组)。 I/ R 组和 P 组阻断腹主动脉40 min,再恢复其血流。 P 组于主动脉阻断前10 min 和再灌注即刻分别静脉泵注丙泊酚30 mg·kg-1,其余两组则在相同时间点给予相同容积0.9%氯化钠溶液。3组动物分别于术后1,2,3,5,7 d 均被随机处死4只动物,取其脊髓组织的 L3-L4段,分别采用酶联免疫吸附测定(ELISA)法检测 SOD1活性,采用实时聚合酶链反应(RT-PCR)法检测SOD1、PI3K、AKT 的 mRNA 的表达水平。结果3组动物脊髓组织 SOD1活性变化：术后第1天,与 S 组比较,I/ R 组、P组 SOD1活性均显著增强(均 P<0.05)；术后第2天,与 S 组比较,P 组 SOD1活性升高(P<0.05),而 I/ R 组则无明显变化(P>0.05)；术后第3~7天,与 S 组比较,I/ R 组 SOD1活性均显著降低(均 P<0.05),而 P 组则无明显变化(均 P>0.05)。利用线性回归分析发现,脊髓组织 SOD1、PI3K、AKT 的 mRNA 表达变化与 SOD1活性的变化呈正相关。结论缺血前和缺血后丙泊酚联合运用可有效防治兔 SCIRI,其作用机制可能与丙泊酚通过激活 PI3K/ AKT 信号转导通路,进而增强脊髓组织中 SOD1的表达有关。%Objective To investigate roles of superoxide dismutase-1(SOD1),phosphatidylinositol 3-kinase (PI3K) /serine/ threonine protein kinase (AKT) signal transduction pathway in protection of propofol on spinal cord ischemic reperfusion injury (SCIRI) in rabbit model before and after ischemia. Methods Sixty Japanese male rabbits were randomly divided into 3 groups (n=20),namely sham-operation group (Group S),ischemia-reperfusion group (Group I/ R) and ischemia-reperfusion group with propofol treatment (Group P). Abdominal aorta of the rabbits in group I/ R and group P were blocked by clamp for 40 min and then the clamp was removed. Propofol (30 mg·kg-1 ) was intravenously infused 10 min before blocking the aorta and at the time of reperfusion. Normal saline was intravenously infused at the same time points in the other two groups. Four rabbits of each group were randomly executed 1,2,3,5,7 days after surgery. Spinal cord tissues at L3-L4 levles were harvested. Bioactivity of SOD1 was detected by ELISA and mRNA expression levels of SOD1,PI3K and AKT were detected by RT-PCR. Results On the 1st day after the surgery,the bioactivity of SOD1 increased significantly in Group I/ R and Group P as compared with that in Group S (P<0. 05). On the 2nd day,compared with Group S,the bioactivity of SOD1 increased significantly in Group P (P<0. 05),but there was no change in Group I/ R (P>0. 05). On the 3rd,the 5th and the 7th day,compared with Group S,the bioactivity of SOD1 decreased significantly in Group I/ R (P<0. 05),but there was no change in Group P (P>0. 05). Linear regression analysis indicated that there was a positive correlation between the changes of SOD1 activity and the mRNA expression of SOD1,PI3K and AKT respectively in spinal cord tissues. Conclusion Pre- and post-ischemic conditioning with propofol shows potent protective effects against SCIRI in the rabbit model. The mechanisms may be related to increased expression of SOD1 in the spinal cord tissues by activating PI3K/ AKT signal transduction pathway.