Study The Effect And Mechanism Of Ischemic Postconditioning On The Limb Ischemic-Reperfusion Injure

Objections:Through the limb ischemia-reperfusion injure experiment, to study whether ischemic postconditioning can play a protect role to limb ischemia-reperfusion injure.To quest a new prophylactico-therapeutic measure about alleviating the limb ischemia-reperfusion injure,and to preliminary investigate the mechanism of ischemic postconditioning.Materials and methods:36 rabbits were randomized into 3 groups: sham operation group(control group),ischemic-reperfusion group(IR group) and ischemic postconditioning group(IPo group).There are 4 rabbits in the control group,16 rabbits in the IR group,16 rabbits in the IPo group. Dividing the IR group into 4 subgroups according to the time after reperfusion:IR-1 group means the rabbits in the group are at the time 1 hour after reperfusion,IR-2 group means the rabbits in the group are at the time 2 hours after reperfusion,IR-4 group means the rabbits in the group are at the time 4 hours after reperfusion,IR-24 group means the rabbits in the group are at the time 24 hours after reperfusion, there are 4 rabbits in every subgroup.The IPo group are also divided into 4 subgroups according to the same method:IPo-1 group,IPo-2 group,IPo-4 group and IPo-24 group.Rabbits in the control group were separated right common femoral artery but weren't blocked by noninvasive serrefine.In the IR group,the right common femoral arteries were blocked for 4 hours with noninvasive serrefine then unclamped to recover reperfusion.IPo group was sequential 1 min reperfusion and another 1 min ischemia for 3 cycles after 4 hours posterior limb ischemia.At the homologous time point,1000mg right gastrocnemius muscle was obtained to prepare tissue homogenate for skeletal muscle's MDA,SOD,MPO test.The other part gastrocnemius muscle was obtained to histological section test.Then blood samples were obtained from right femoral vein to blood serum's CPK,LDH,MDA,SOD test.Results:(1) Results of MDA test:The content of MDA in IR and IPo groups was higher than control group,there were significant difference (P＜0.01).Moreover,the content of MDA was gradual increased with time passed within 4 hours after reperfusion.The content in IPo subgroups was lower than corresponding groups of IR group,there were significant difference between IR group and IPo group(P＜0.05).(2)Results of SODt est: The content of SOD in IR and IPo groups was lower than control group, there were significant difference(P＜0.01).Moreover,the content of SOD was gradual reduced with time passed within 4 hours after reperfusion. The content in IPo subgroups was higher than corresponding groups of IR group,there were significant difference between IR group and IPo group (P＜0.05).(3)Results of MPO test:The content of MPO in IR and IPo groups was higher than control group,there were significant difference(P＜0.01). Moreover,the content of MPO was gradual increased with time passed within 4 hours after reperfusion.The content in IPo subgroups was lower than corresponding groups of IR group,there were not significant difference between IR group and IPo group(P＞0.05).(4)Results of CPK and LDH test: The contents of CPK and LDH in IR and IPo groups were higher than control group,there were significant difference(P＜0.01).Moreover,the contents of CPK and LDH were gradual increased with time passed within 24 hours after reperfusion.The content in IPo subgroups was lower than corresponding groups of IR group,there were significant difference between IR group and IPo group(P＜0.01).(5)Results of histological section test:There were myocyte and interstitial substance edema,muscle fiber fracture and lots of inflammatory cell infiltration at each time in IR and IPo groups.But these pathomorphological changes in IPo subgroups were alleviated than corresponding groups of IR group.Conclutions:Ischemic postconditioning can protect the skeletal muscle against reperfusion injury by decreasing the produce of AOS, increasing the ability of oxidation resistance and alleviating the lipid peroxidation.But the gather of neutrophilic granulocyte was obvious alleviated.Further researches need be done to understanding the precise mechanism of ischemic postconditioning.