| ObjectiveTo investigate the effects of postconditioning on SD rat's brain apoptosis induced by brain ischemic/reperfusion and its mechanism.Collecting brain tissue homogenate to measure the level of MDA and SOD.Discussing the brain—protective mechanism of postconditiong and the potential clinical application.MethodsMale SD rats weighting 250-300g,were anesthentized by 10%chloral hydrate peritoneal injection.Rats were randomly divided into five groups.(1)The sham group;(2)ischemic/reperfusion 1 group:brains were subjected to 30min of ischemia followed by 24 hours of reperfusion(I/R1 group);(3)ischemic/reperfusion 2 group: brains were subjected to 30min of ischemia followed by 48 hours of reperfusion(I/R2 group);(4)postconditioning 1 group:brains were subjected to 30min of ischemia followed by three circles of 15s/15s'postconditioning and 24 hours of reperfusion(Post1 group);(5)postconditioning 2 group:brains were subjected to 30. min of ischemia followed by three circles of 15S/15s'postconditioning and 24 hours of reperfusion(Post2 group).All of the groups were assigned 8 rats.Bilateral common carotid artery were dissociation and occlusion for 30min followed by reperfusion or reperfusion plus postconditioning.At the end of the experiment,all of the rats were killed.The brain tissue homogenate were collected in order to measure the level of MDA and SOD.Brain tissue were stored in 10%formaldehyde solution, followed by paraffin section and measurement of the apoptosis index.ResultsIn I/R1,I/R2,Post1,Post2 groups,MDA were higher than in sham group,SOD were lower than in sham group(P＜0.05).Comparing the SOD,the Post1 group was higher than in I/R1 group and the Post2 group was higher than in I/R2 group(P＜0.05); comparing the MDA,the Post1 group was lower than in I/R1 group and the Post2 group was lower than in I/R2 group(P＜0.05).Comparing the SOD,the I/R2 group and the Post2 group were respectively higher than in I/R1 group and Post1 group(P＜0.05); comparing the MDA,the I/R2 group and the Post2 group were respectively lower than in I/R1 group and Post1 group(P＜0.05).In the sham group,there was low level apoptosis,while in I/R1,I/R2,Post1, Post2 groups,the apoptosis were obviously.The apoptosis index in Post1 group and Post2 group were respectively lower than in I/R1 and I/R2 group(P＜0.05).The apoptosis index in I/R2 group and Post2 group were respectively lower than in I/R1 and Post1 group(P＜0.05).Conclusion①The ischemic/reperfusion of brain could induce brain cell apoptosis;②Postconditioning could inhibit brain cell apoptosis induced by brain's ischemic/reperfusion;③Postconditioning could inhibit lipid peroxidation reaction induced by brain's ischemic/reperfusion.
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