The Effect Of Pretreating With Oleanolic Acid On The Glycogen Content During Hepatic Ischemic Reperfusion In Rats

Objective: To observe the effect of pretreating with Oleanolic acid(OA) on the glycogen content, ALT activity and morphological changes during hepatic ischemic reperfusion (IR) in rats.Methods: 128 Male Sprague-Dawley(SD) rats were randomly assigned into sham(Group A, n=32), IR(Group B, n=32), 0.5%sodium carboxymethycellulose (CMC-Na)( Group C , n=32), OA +0.5% CMC-Na(OA= 20mg/ml)( Group D , n=32). Each group was then divided into 4 subgroups on the following times: before operation, at 0h, 3h, 6h after reperfusion. Before the operation all rats got intragastric administration one time a day for seven days, groupD with OA(100mg/kg) +0.5% CMC-Na, GroupA and B with water of the same volume as group D;groupC with 0.5% CMC-Na of the same volume as above. At the eighth day, operations were done on the rats. After anaesthesia, the hepatic peripheral ligament got separated without occlusion of liver blood flow in group A, and warm partial(70%) hepatic ischemic reperfusion model was established by clamping of the middle and left branches of liver arteries with nontraumatic serrefines for 60 minutes and then reperfusing in groupB,C,D . For all rats, 4 ml blood were drawn from inferior caval vein before operation, at 0h, 3h, 6h after reperfusion. Then after centrifugalization, 1.5ml blood serum was taken to measure the activity of ALT, rats were killed and liver tissues were taken out immediately to measure glycongen content, lactate level and check the changes of histological pathology through light microscope. All data were expressed as mean±SD, statistical analysis was performed using SPSS 13.0 and P value of<0.05 was considered significant.Results: (1)Glycongen content: Before operation, the glycongen content of groupD increased significantly compared with those of other groups(P<0.05) respectively. The glycogen contents of groupB, C, D decreased significantly compared with that of group A at 0h, 3h, 6h after reperfusion respectively (P<0.05); The glycogen contents of groupD were higher than that of groupB or group C respectively(P<0.05). (2)Lactate level: The lactate level of groupD increased significantly compared with those of other groups respectively at 0h after reperfusion (P<0.05); The lactate levels of groupB and groupC increased significantly compared with that of groupA respectively (P<0.05) . (3)ALT activity: The activity of ALT of groupB, C, D increased significantly compared with that of groupA(P<0.05) at 3h, 6h after reperfusion; The activity of ALT of groupD decreased significantly compared with that of groupB or groupC respectively(P<0.05). (4) Morphologic changes: There were typical pathological changes of hepatic IR injury in groupB, groupC, groupD and those in groupD were attenuated compared with groupB, C.Conclusion: Pretreatment with OA can provide significant protection against warm partial hepatic IR injury in rats. The mechanism of OA pretreatment may be increasing the glycogen content.