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Postconditioning, a series of mechanical interruptions of reperfusion after ischemia. The extensive studies of postconditioning indicated that have protective effects of postconditioning against ischemia from the heart, the brain and many other organs. HIF-1αand HO-1 are two important factors which have been found have protective effects of reperfusion after ischemia. Master Chen Guanglei in our department had established rat model of kidney ischemia postconditioning. Moreover, we researched on how works of postconditioning in the field of HIF-1αand HO-1.Objective: To investigate the effect of ischemic postconditioning on expression of HIF-1αand HO-1 protein in rats after kidney ischemia reperfusion injury.Methods: 72 SD rats were randomized into 3 groups: sham operation group(S group), ischemic reperfusion group(IR group) and ischemic postconditioning group(IPO group). Each group had 0.5h, 1h, 3h, 6h, 12h, 24h, 48h and 72h subgroups. Rats in S group were separated left renal artery and ligatured right one, then they were exposed for 45 min. In IR group, left renal artery was induced by clamp for 45 min soon after reperfusion, which was based on method of S group. IPO group was sequential 20 sec reperfusion and another 20 sec ischemia for 10 cycles after 45 min kidney ischemia. After operation, all the rats were raised in metabolic cages and had food and drink freely. Then the blood samples were draw from the inferior vena cava and the nephridial tissues were fixed at each time stage. The blood urea nitrogen and creatinine were detected by chemical method and the NAG enzyme was detected by biochemical methods. The expression of HIF-1αand HO-1 protein was detected by immunohistochemistry staining technique and Western blot.Results: Compared with the S group, the levels of blood urea nitrogen and the serum creatinine were all step up in IR and IPO group.The peak time of IR group was at 6h after the operation(98.47±2.69U/L), and peak time of IPO group was at 3h(99.78±7.91 U/L) .At 6h, the NAG of IPO group was obviously lower than IR group,[IPO group(42.43±20.69)U/L vs IR group(46.50±40.25)U/L ,P﹤0.05]. The urinates the NAG enzyme IPO group overall to be lower than the IR group, [IR group(98.47±2.69)U/L vs IPO group(40.51±1.44)U/L, P﹤0.05].By immunohistochemistry method, we can get the expression of HIF-1αin IPO group were significantly higher than IR group at 6h after the operation,( IPO group:5.20±1.09 vs IR group: 3.20±0.84, P﹤0.05).These were coincidence with them in the western blot, (IPO group:1.04±0.05 vs IR group:0.92±0.02, P﹤0.05). It were proved by western blot that the expression of HO-1 in IPO group were higher than IR group at 3h after the operation(IPO group:0.76±0.07 vs IR group:0.69±0.01, P﹤0.05).Conclusion: Ischemic postconditioning can increase the expression of HIF-1αand HO-1. At the same time, it can extend HIF-1αpeak time in rats after kidney ischemia reperfusion injury, which could attenuate the injury from kidney ischemia reperfusion.
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