| BackgroundIn recent years, The earthquake disaster happened frequently in China, in which crush syndrome (CS) is the second cause of death in casualties after the earthquake. Besides, direct trauma to death is the first one. Ischemic Post-conditioning (Ischemic Post-conditioning, IPost) is a new treatment method of schemia reperfusion injury. So we want to find whether it play the same role in crush injury syndrome? In this topic, The protective role of Ischemic Post-conditioning in different time on crush injury syndrome is evaluated.ObjectiveI. Establish a repeatable rabbit CS model.II. Screen the best time-window of ischemia postconditioning for rabbit CS injury protective effect.III. Verify the protective effect of noninvasive ischemia postconditioning on rabbit CS injury.MethodCompress (1 OOKpa,8h) a single lower limb of rabbits by using an automatic pneumatic tourniquet to establish a CS model, and then select and randomly divide 56 healthy Japanese white rabbits with weighs of 2.3±0.2Kg into seven groups (n=8) as follows:S Group (Sham Group) is sham operation control group:After compressing and modeling for eight hours, free the femoral artery and vein in the groin of both lower limbs, and suture the incisions of the both lower limbs after one hour.IPA Group (5x5s/5s) is ischemia postconditioning A group:After compressing and modeling for eight hours, free the femoral artery and vein in the groin of both lower limbs, immediately clip the arteries and veins with bulldog clamp for 5 seconds after decompressing and reperfuse for 5 seconds with 5 cycles, and at last suture the incisions of the both lower limbs after one hour.IPB Group (5×30s/30s) is ischemia postconditioning B group:After compressing and modeling for eight hours, free the femoral artery and vein in the groin of both lower limbs, immediately clip the arteries and veins with bulldog clamp for 30 seconds after decompressing and reperfuse for 30 seconds with 5 cycles, and at last suture the incisions of the both lower limbs after one hour.IPC Group (5×lmin/lmin) is ischemia postconditioning C group:After compressing and modeling for eight hours, free the femoral artery and vein in the groin of both lower limbs, immediately clip the arteries and veins with bulldog clamp for 60 seconds after decompressing and reperfuse for 60 seconds with 5 cycles, and at last suture the incisions of the both lower limbs after one hour.IPD Group (5x5min/5min) is ischemia postconditioning D group:After compressing and modeling for eight hours, free the femoral artery and vein in the groin of both lower limbs, immediately clip the arteries and veins with bulldog clamp for 5 minutes after decompressing and reperfuse for 5 minutes with 5 cycles, and at last suture the incisions of the both lower limbs after one hour.IPE Group (5×10min/10min) is ischemia postconditioning E group:After compressing and modeling for eight hours, free the femoral artery and vein in the groin of both lower limbs, immediately clip the arteries and veins with bulldog clamp for 10 minutes after decompressing and reperfuse for 10 minutes with 3 cycles, and at last suture the incisions of the both lower limbs after one hour.IPF Group (5×1min/1min) is noninvasive ischemia postconditioning F group:After compressing and modeling for eight hours, immediately bind the both lower limbs with spinning-type tourniquet for 1 minute after decompressing and reperfuse for 1 minute with 5 cycles.During the course of the experiment, connect to the multi-channel physiological signal acquiring system respectively through the ear arterial tubes, and measure the artery pressure, heart rate and blood biochemical index detection (MAP, K+, Scr, BUN, CK, NGAL, Mb and IL-6) at 7 time points:before compression, during decompression and 2h,6h,12h,18h and 24h after decompression. At the same time, observe the changes in the vital signs and local symptoms of rabbits.Result After decompression, all the rabbits in each group showed depression, tachypnea, decreased heart rate and hypothermia. Within 24 hours after decompression, only 17 dead rabbits were discovered (three in S Group, two in IPA Group and IPD Group and three in IPE Group and IPF Group) between 18 hours and 24 hours after the decompression. After 2 hours of decompression, all the rabbits in each group showed decreased urine output with deepen colors, and even myoglobinuria; after 18 hours of decompression, no urine was found in each group, and the amounts of urine output among the group were not statistically significant.After decompression, MAP of all the rabbits in each group gradually increased, and peaked at 2 hours after decompression, and then gradually decreased. Compared to S Group, blood indexes of the ischemia postconditioning groups were lower; among some blood indexes (CK, Scr, K+, MB, BUN, IL-6 and NGAL), the decrease of IPC Group and IPD Group (1-5min) was more obviously after 2 hours of decompression and has statistical significance in comparison to other groups, with IPC Group of the most dramatic reduction.The noninvasive ischemia postconditioning group (IPF Group), performing reperfusion to both lower limbs with spinning-type tourniquet (5×lmin/lmin), further verified its protective effect. And the results show that in terms of the variance analysis about each blood index between IPF Group and IPC Group, there is no significant difference between the two groups.ConclusionⅠ. Compressing (100Kpa) the rabbits’single lower limb for 8 hours by adopting an automatic pneumatic tourniquet enables to establish a model of crush syndrome.Ⅱ. Performing 1-5min remote ischemia postconditioning for 5 cycles to the both lower limbs of rabbits with crush syndrome may produce effective protection to organism injuries, and cut the death rate within 24 hours; among these groups, IPC Group showed the most obvious effect.Ⅲ. Performing lmin remote ischemia postconditioning by spinning-type tourniquet for 5 cycles to the both lower limbs of rabbits with crush syndrome can also produce effective protection to organism injuries. |
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