| Objective:By researching the effect of ischemia-reperfusioninjury in rats after ischemic preconditioning on the early brainstemischemia-reperfusion and observing the changes of BAX、GSH-px, to reveal the possible mechanism of neuroprotection of ischemic preconditioning on the brainstem, and provide the basis for ischemia tolerance enhanced of brainstem， And provided the basis for the choiceof the thrombolytic time window of brainstem infarction particularafter TIA recurrent in clinical.Methods:1The160male SD rats,weighting300-320g,Were randomly divided into Sham operation group,Ischemia group,Ischemia-reperfusion group,Ischemic preconditioning group(Ischemia group were divided into ischemic1h、2h、3h、4h、5h,Ischemia-reperfusion group were divided into Ischemia1h and reperfusion7h,2h and then reperfusion6h,3h and then reperfusion5h,4h and then reperfusion4h,5h and then reperfusion3h five time points. Everyobservations point had eight rats in each group.Ischemic preconditioning group were given to the whole brain ischemic preconditioning3minutes at first,72hours later and then given to the brainstem ischemia-reperfusion.Each time point Similar to the ischemia-reperfusion group.2Ischemia group clamped the basilar artery at the corresponding time. Interval at different time points after ischemia-reperfusi on group using micro artery clip clipping of the basilar artery to open the artery clip recanalization. The ischemic preconditioning groupused improved pulsinelli four vessel occlusion method to giving the ischemcpreconditioning group3minutes whole brain ischemic preconditioning,and after three days prepare for the brainstem ischemia-reperfusionmodel. Each group model was successful and included in the experiment were sacrificed at corresponding time points.3By HEstaining and light microscope to observe the changes in cell structure.4Useing TTC staining and brain stem BAEP observed brainstem ischemia scope and Degree.5By immunohistochemistry to observe changes of BAX.6Useing enzyme-linked immunosorbent assay (ELISA)method to observe the changes of GSH-PX. Results:（1）HE staining showed normal morphology of sham operation group of nerve cells;With the prolonged ischemic time, Ischemia group gradual emergence of cell edema、Inflammatory response、Nucleus condensation and the performance of gradually increase.Ischemia-reperfusion group and the ischemic preconditioning group had similar performance.Compared with the ischemia group,befor4h Ischemia groupcell damage ismore serious injury than the ischemia-reperfusion group; Befor5h,the injury of ischemic preconditioning group cell not only lighter than ischemia group but also lighter than ischemia-reperfusion group.(2)TTC staining showed that the sham operation group at all time poin ts showed no ischemic manifestations. The remaining threegroups of1h were no obvious ischemic manifestations;Befor4h, ischemia-reperfusion group were less than the ischemic group; Befor5h,the injury of ischemic preconditioning group cell not only lighter than ischemia group but also lighter than ischemia-reperfusion group.(3)BAEPchanges:In each experimental group of ischemic（reperfusion group pretreated group in1h time point except）, every waves(except Ⅰwave) of PL and IPL were longer than the sham group(P>0.05); At the time of1h、2h、3h in ischemia-reperfusion group,every waves(exceptⅠ w ave) of PL and IPL were shorter than ischemic group corresponding time;At the time of1h、2h、3h、4h in ischemic preconditioning group,every waves(exceptⅠ wave) of PL and IPL were shorternot only than ischemic group corresponding time,but also shorter than ischemia-reperfusion group corresponding time.(4)The BAX of immunohistochemical Shows:In each experimental group of ischemic,BAX were greater than sham operation group at each time(P<0.05);At the time of1h、2h、3h in ischemia-reperfusion group,BAX wereless than ischemic group corresponding time(P<0.05);At the time of1h、2h、3h、4h in ischemic preconditioning group,BAX were less not only than ischemic group corresponding time,but also shorter thanischemia-reperfusion group corresponding time(P<0.05).(5)Changes of the GSH-Px activity:In each experimental group of ischemic,the G SH-Px activity were lesser than sham operation grou-p at each time(P<0.05);At the time of1h、2h、3h in ischemia-reperfusion group,theGSH-Px activity were greater than ischemic group corresponding time(P<0.05);At the time of1h、2h、3h、4h in ischem-ic preconditioning group,the GSH-Px activity were greater not only than ischemicgroup corresponding time,but also greater than ischemia-reperfusion group corresponding time(P<0.05).Conclusion:(1)Ischemic preconditioning model and brainstem ischemia and reperfusion model was simple、economic, practical. Brainstemischemia and reperfusion model clipping the first and second non-branching area of basilar artery,and the ischemia of the model are stab-le, and the animal have low mortality.(2) BAEP can reflect the brainstem ischemia and reperfusion injuryextent sensitively,and the trend showed that ischemic preconditioningcan be extended to the brainstem reperfusion time window.(3)Ischemic preconditioning can extend the reperfusion time windowof brain stem by down-regulating BAX expression, raising the GSH-Px activity expression, and alleviate Significantily brain stem ischemia-reperfusion injury.. |
PDF Full Text Request