Role Of Changed Na～+-K～+ ATPase Activity In Rat Liver Ischemia-reperfusion Injury

objective:To study the change of Na⁺-K⁺ATPase activity and the effect during hepatic ischemia-reperfusion injury in the rat. Methods: 120 healthy male SD rats were randomly divided into two groups:the sham-operated group (SO, n=60) and the ischemia-reperfusion group (I/R n=60).Both groups were randomly subdivided into six groups, every group had ten rats. In ischemia-reperfusion group, hepatic reperfusion by interruption of the arterial and portal venous blood supply to the left lobes and middle lobes of liver. In sham-operation group, midline laparotomy was performed without vascular occlusion, one half of each group animals were planted a catheter into common bile duct at the time point 0,1, 2, 6, 24, 72h after hepatic reperfusion.Bile juice was collected to determine the concentration of total bile acid (TBA) one hour's after reperfusion meanwhile, another half of each group blood in venous was collected at the same time point to determine the concentration of alanise transaminase(ALT) and total bile acid (TBA), after that,liver specimen was taken to test the content of malonaldehyde(MDA), the activity of Na+-K+ ATPase and intracelluar free cacium ([Ca²⁺]i) in hepatic.Results: In ischemia-reperfusion group, the activity of Na + -K + ATPase reduced immediately following 1h of ischemia, falling to the lowest at 2h after reperfusion, its recovery at 72h after reperfusion. Plasma ALT , TBA and liver MDA and the intracellular free calcium([Ca²⁺]i) concentrations increased markedly after hepatic ischemia-reperfusionand reached maximal at 6h , but the amount of bile juice markedly decreased and rapidly droupped to the lowest at 2h. the activity of Na + -K + ATPase had a signifant negative correlation with the serum ALT, TBA andliver MDA, intracellular[Ca2+]i, a signifant positive correlation with the amount of bile juice and TBA of bile at the time point 0,1, 2, 6, 24h after hepatic reperfusion, and they had no correlation at 72h after reperfusion.Conelusion ilschemia-reperfusion injury can lead to the reduction ofNa + -K + ATPase activity. The reduction of Na + -K + ATPase activity played a important role in hepatic injury.