Effect of Ischemic Preconditioning on the expression of blood plasma MDA, SOD and AQP4 mRNA of spinal cord

Objective To investigate the protective effect of Ischemic preconditioning (IPC) on the expression of MDA,SOD and AQP4 mRNA of spinal cord following abdominal aorta occlusion.Methods Fifty-four SD rats were randomly divided into three experimental groups:group Sham,group I/R and group IPC.In group Sham,only laparotomy was performed without further treatment.In group I/R (ischemia reperfusion injury group),a 60 min abdominal aorta occlusion was induced with bulldog clamping.In group IPC,preconditioning of 5 min ischemia and 5 min unclamp by the clamping abdominal aorta were followed by 60 min of reperfusion.At times of 12 hours,1,2,5,10 days after reperfusion behavior scores were respectively given.The contents of malondialdehyde (MDA) and superoxide dismutase (SOD) in blood plasma were determined with enzyme-labeled instrument.Real-time PCR was used to detect the AQP4 mRNA in different treated groups.Results After operation 54 SD rats were all survival.Behavioral score of group I/R decreased until 5 days after reperfusion and the scores of group IPC were all higher than group I/R,by increasing as time went by.The SOD content of group I/R 24-h after reperfusion was dramatically decreased than group Sham,and the MDA contents were all lower(P ＜ 0.05) than group Sham.In group IPC the contents of SOD and MDA showed no significance with group Sham.At the same time,compared with group Sham,AQP4 mRNA expression of group I/R in spinal cord after reperfusion 2 days showed obviously statistical increasing (P ＜ 0.01),and that of group IPC after reperfusion 1 day showed increasing(P ＜0.05),and then AQP4 mRNA expression was kept decreasing until 5 days after reperfusion.The peak value of AQP4 mRNA in group IPC was lower than group I/R (P ＜0.01).Conclusion Ischemia preconditioning in rats could protect spine from I/R injury by reducing oxidative stress and AQP4 mRNA expression. Key words: Ischemic preconditioning; Ischemia-reperfusion; Malonaldehyde; Superoxide dismutase; Aquaporins 4