Effects Of Nimodipine On The Expression Of AT1/AT2 In Brain Stem After Subarachnoid Hemorrhage

Objective:To investigate the effects of nimodipine on the changes of AT1,AT2,Akt,P65 in brain stem after subarachnoid hemorrhage in rats,discussion of the brain Injury mechanism induced by SAH.Method:1. 40 Wistar rats were used and divided into 5 groups:sham operation group(n=8); SAH1d group(n=8),SAH1d+N group(n=8),SAH14d group(n=8),SAH14d+N group (n=8).Model preparation process:Uses 10% hydration trichloroacetal dehyde acetochloral (300mg/kg) abdominal cavity anaesthesia the wistar rats,Incision skin in a hollow (the included angle forms by the cerebellum medulla oblongata)approximately 0.5cm next external occipital protubeRNAce,approximately 3cm,full exposed atlas,and see the white mambRNAa atlantooccipitalis posteriorta.The sham-operation group injected into physiological saline 0.3ml to the cisterna magna;The SAH model group, injected into autologous blood 0.3ml two times,the blood was drawn from the ophthalmic venous plexus;The SAH model gives nimodipine treatment group injects into nimodipine 0.2mg/kg,in the SAH latter 30 minutes abdominal cavities.2. Using the neuroethology loeffler 5-point scale methods for evaluation.5 points: When holds the back,the rats can normal movement,and stand up from failure in 5S;4 points:The independent movement reduces,and still turning over in 5S;3points:>5S turning over;2 points:Cannot stand up from failure;1 point:Cannot the movement.3. Cistern in rats injected in the blood before the operation,cistern after blood injection and after administration of nimodipine 1 and 14 days in the intraperitoneal injection of anesthesia, transcranial Doppler ultrasonography of the largest rat basilar artery blood flow velocity in order to determine the degree of cerebral vasospasm.4. Specimens by 4% paraformaldehyde-fixed,paraffin-embedded,consecutive run sections,the thickness of 4μm,conventional HE staining and observed the cell morphology.5. Western blotting was used to analyze the expression of AT1,AT2,Akt,p65.Results:1. After SAH in rats showed neurological behavior:SAHld group score compared with the sham-operated group decreased significantly after application of nimodipine score increased;with the time,SAH14d group and SAH1d group,the neurological score significantly increased after application of nimodipine and further increased.2. After SAH in rats showed that transcranial Doppler ultrasonography:Group SAH1d basilar artery blood flow compared with the sham-operated group significantly accelerated blood flow after application of nimodipine at a slower rate; SAH14d group and the group velocity SAH1d have decreased after application of nimodipine further reduce the blood flow velocity slow.3, SAH rats after HE staining showed that the brain stem: SAH1d group of bleeding lesions can be seen clearly and significantly reduced the number of neurons, cytoplasmic shrinkage,cell density increased,and swelling of glial cells,cells after application of nimodipine injury state of improvement,but still can be seen scattered small hemorrhagic foci;SAH14d group compared with hemorrhagic foci SAH1d a significant decrease in the number of neurons increased,the cell state of improvement, application of nimodipine further improvement after the cell state. 4. SAH1d Group AT1 protein expression compared with the sham group significantly increased after application of nimodipine decreased AT1 expression; SAH14d group and SAH1d group decreased compared to the expression of AT1, nimodipine after application no significant changes.5. SAH1d Group AT2 protein expression compared with the sham group significantly increased after application of nimodipine decreased AT2 expression; SAH14d group and SAH1d group decreased AT2 expression,application of nimodipine and no significant change.6. SAH1d Group Akt protein expression compared with sham-operated group decreased significantly after application of nimodipine significantly increased Akt expression; SAH14d group and Akt expression SAH1d group increased after application of nimodipine had no significant changes.7. SAH1d group of p65 protein expression compared with sham-operated group decreased significantly after application of nimodipine significantly increased p65 expression;SAH14d Group SAH1d compared with the expression of p65 increased after application of nimodipine had no significant changes in.Discussion:Subarachnoid Hemorrhage have been the medical research hot spots because of its high mortality and disability rate.How to prevent or delay the genesis of Apoptosis is a important enlightenment for clinical on the prevention and treatment of cerebral vasospasm.Therefore,it is is very essential to establishes a kind,stable,the reliable animal model for study the Pathophysiological Mechanism of SAH.The results of this study show that,SAH group,AT1,AT2 protein expression were higher than sham-operated group,after application of nimodipine decreased.Note the expression of AT1 increased intracranial vasoconstriction after SAH,blood pressure increased,the incidence of CVS increased,AT2 expression increased apoptosis increased,so AT1, AT2 will further add to the increased brain damage.SAH group Akt,p65 protein expression is lower than the control group,after application of nimodipine have increased.Akt,p65 expression decreased,and their role in suppression of apoptosis is inhibited,thereby aggravating the brain injury.Conclusion:1. The rat's neurobehavior decreased significantly,basilar artery blood flow increased accelerate and numbers of Neurons decreased significantly.Show that Successful set up of the model of SAH.2. Acute phase of SAH through the increase of local AT1, AT2 expression, enhance the vasoconstriction, and promote apoptosis, caused by brain damage.3. The increase in AT1 and AT2 may also promote survival by inhibiting the Akt signaling pathway, thereby inhibiting downstream of p65, increase the brain damage.4. Nimodipine in the acute phase of SAH has a significant protective effect of the brain, which may be related to a direct reduction of local AT1, AT2 expression, inhibition and angiotensin AT1, AT2 and promote apoptosis, but also may be related, directly or indirectly, and the increase in Akt p65-related.