| Objectives Explore Delayed limb ischemic postconditioning on cerebral ischemia reperfusion in rats,and analyze whether this protective effect is related with the regulation of Eph A2 and Aβ in the brain ischemic cerebral hemisphere.Methods 264 male SD rats were randomly divided into 3 groups, sham operation group(n=24), simple ischemia-reperfusion group(n=120), Delayed limb ischemic postconditioning group(n=120), according to the different time,each group are divided into 1d,2d,3d,4d and 5d.18 rats in each group only. After MCAO model, clipping the double femoral artery by turns 2 minutes, each of the 5 period, all 5 days. Comparison of the right brain infarct volumes, water content, Evans blue content, the positive cells of Eph A2 and Aβ.Results 1 Compared with the sham operation group, the brain infarct volumes of simple reperfusion and delayed limb ischemic postconditioning at each time point on the right side of are higher(P<0.05). At the first day, the infarct volumes is almost equal in the simple reperfusion group and delayed limb ischemic postconditioning group.From the second day to the fifth day,the infarct volume of the simple reperfusion group is significantly higher than(P<0.05), and maximum value is higher than the former.From the third day to the fifth day,the infarct volumes of all groups have no obvious change.2Compared with the sham operation group, simple ischemia reperfusion and delayed limb ischemic postconditioning on the right brain tissue water content were higher at each time(P<0.05). Starting from the second day, The water content in the simple ischemiareperfusion group was significantly higher than that in delayed limb ischemic postconditioning group(P<0.05), and while both are the second day to reach the pinnacle of cerebral edema, but the maximum water content of the former is higher than the latter;The water content in simple ischemia-reperfusion group decreased slowly,delayed limb ischemic postconditioning group with the increase of the number of limb ischemic postconditioning decreased gradually.3 The EB content in the right side of the brain tissue in simple Ischemia-reperfusion group and delayed limb ischemic postconditioning group was higher than that in sham operation group(P<0.05). Starting from the second day, EB content in the simple Ischemia reperfusion group was significantly higher than that of delayed limb ischemic postconditioning group(P<0.05);it was reached the peak at the second day, but the maximum delay limb ischemic postconditioning group was less than that of the simple Ischemia-reperfusion group; The decline rate in the simple Ischemia-reperfusion group was significantly lower than delayed limb ischemic postconditioning group.4 The number of Eph A2 positive cells in simple Ischemia-reperfusion group and delayed limb ischemic postconditioning group area around the cerebral infarction were significantly higher than those in the sham operation group(P<0.05)at each time point.Compared with the simple ischemiareperfusion group at each time point, the number of positive cells in delayed limb ischemic postconditioning group were significantly lower(P<0.05).The number of Eph A2 positive cells in simple Ischemia reperfusion group began to increase at the first day, reached the peak at the second day,the third day began to fall; delayed limb ischemic postconditioning has the same change tendency,but the peak value was significantly lower than that of the former, and the decrease rate was faster than the former.5 The number of Aβ positive cells in delayed limb ischemic postconditioning group and simple ischemia reperfusion group area around the cerebral infarction were significantly higher than those in the sham operation group(P<0.05)at each time point. Compared with the simple ischemia reperfusion group at each time point,the number of positive cells in delayed limb ischemic postconditioning group were significant-ly lower(P<0.05).The number of Aβ positive cells in delayed limb ischemic postconditioning began to increase at the first day, reached the peak at the second day,the third day began to fall; Simple Ischemia-reperfusion group has the same change tendency,but the peak value was significantly higher than that of the former, and the decrease rate was slower than the former.Conclusions 1 The expression of Eph A2 and Aβ increased around the ischemia after acute cerebral infarction in rats.2 Delayed limb ischemic postconditioning may inhibit the expansion of infarct size and reducing the degree of brain edema after cerebral infarction, and its mechanism may be related to inhibiting the expression of Eph A2 and Aβ. |
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