Experimental Study The Neuroprotective Role Of Atorvastatin On Early Brain Injury In Rabbits After Subarachnoid Hemorrhage

Objective: To study the Neuroprotective about brainstem and hippocampus of Atorvastatin on early brain injury in Rabbits after subarachnoid hemorrhage by clinical behavior scale、Immunohistochemistry and TUNEL method.Methods: Thirty-two healthy male New Zealand Rabbits weighting between 2kg and 2.5kg were randomly allocated into four groups: SAH group(n=8), control group(n=8), SAH+placebo group(n=8), SAH+Atorvastatin group(n=8). All subarachnoid hemorrhage animals models were established by remove a 1cm*1cm skull and injected 1 ml/kg fresh autologous arterial blood into prechiasmatic cistern in 60 s. Control group did not inject fresh autologous arterial blood and just remove a 1cm*1cm skull, SAH+Atorvastatin group received 5mg/kg oral drops as Atorvastatin at post-SAH hours 4h, 16 h,28h and 40 h. SAH+placebo group received the same procedure but the oral drops was starch. All rabbits brain samples such as brainstem and hippocampus were extracted at 48 hours after SAH models was established successful. We observed the clinical behaviors function after experimental SAH by the same observer, and measured the expressions of Bcl-2 and Bax by immunohistochemistry; the Neuron apoptosis of brainstem and hippocampus was detected by TUNEL method at 48 hours after SAH.Results: To compared with control group, clinical behavior function impairment caused by SAH was evident in SAH subjects(P < 0.01); It had no significant difference between SAH group and SAH+placebo group. Atorvastatin treatment group showed a better performance and good nerve functional score than placebo treatment group(P<0.05). Immunohistochemical study showed that positive of Bcl-2 and Bax were mainly located the brainstem and hippocampus neurons with little expression. SAH group and SAH+placebo group had a higher positive rate than control group on Bcl-2 and Bax(P<0.01). There was no statistically significant difference between SAH group and SAH + placebo group(P > 0.05). In SAH+Atorvastatin group, the positive of Bax in this study was significant decreased(P<0.05) and the Bcl-2 was significantly up-regulated(P<0.05). No significantly difference between SAH group and SAH+placebo group(P > 0.05).Conclusions: 1. To compared with control group, clinical behavior function and nerve functional score impairment caused by SAH was evident in SAH rabbits, and SAH also promoted the brainstem and hippocampus neurons apoptosis. 2. Post-SAH Atorvastatin can significantly inhibit the neuronal apoptosis so as to protect the neurons of brainstem and hippocampus at early time.Objective: To study the early brain edema and its relationship with AQP4 in Rabbits after subarachnoid hemorrhage by Western Blot and dry-wet method..Methods: Thirty-two healthy male New Zealand Rabbits weighting between 2kg and 2.5kg were randomly allocated into four groups: SAH group(n=8), control group(n=8), SAH+placebo group(n=8), SAH+Atorvastatin group(n=8). All subarachnoid hemorrhage animals models were established by remove a 1cm*1cm skull and injected 1 ml/kg fresh autologous arterial blood into prechiasmatic cistern in 60 s. Control group did not inject fresh autologous arterial blood and just remove a 1cm*1cm skull, SAH+Atorvastatin group received 5mg/kg oral drops as Atorvastatin at post-SAH hours 4h, 16 h,28h and 40 h. SAH+placebo group received the same procedure but the oral drops was starch. All rabbits brain samples were extracted at 48 hours after SAH models was established successful. Brain edema was detected by dry-wet method after experimental SAH; We measured the expressions of AQP4 by western blot and Nissl,s staining to observe the neuronal apoptosis at 48 hours after SAH.Results: The study showed brain edema was appeared at early time after SAH, To compared with control group, The levels of AQP4 and cerebral content of water was significantly increased(P < 0.01); It had no significant difference between SAH group and SAH+placebo group. Atorvastatin treatment group showed a lower expression of AQP4 and brain edema than placebo treatment group(P < 0.01). No significantly difference between SAH group and SAH+placebo group(P > 0.05).Conclusions: 1. Brain edema appeared at early time and closely related to the expression of AQP4. 2. Post-SAH Atorvastatin can significantly decreased the expression of AQP4 and improve the function of blood-brain barrier(BBB), so as to alleviate the brain edema.Objective: To explore the Vascularprotective of Atorvastatin on early brain injury in Rabbits after subarachnoid hemorrhage by RT-PCR、Immunohistochemistry and H&E staining.Methods: Twenty-four healthy male New Zealand Rabbits weighting between 2kg and 2.5kg were randomly allocated into three groups: SAH group(n=8), sham group(n=8), SAH+Atorvastatin(n=8). All subarachnoid hemorrhage animals models were established by remove a 1cm*1cm skull and injected 1 ml/kg fresh autologous arterial blood into prechiasmatic cistern in 60 s. Sham group did not inject fresh autologous arterial blood and just remove a 1cm*1cm skull, SAH+Atorvastatin group received 5mg/kg oral drops as Atorvastatin at post-SAH hours 4h, 16 h,28h and 40 h. All rabbits brain samples were extracted at 48 hours after SAH models was establishedsuccessful. We measured the expressions of v WF and TM by immunohistochemistry; the m RNA levels of v WF and TM by RT‐PCR. We also measured the degree ofvasospasm of basilar artery by H&E staining to observe the pathological changes(T).Results: RT‐PCR analysis for Detecting the m RNA of v WF and TM at a low level in the rabbits brain in sham group, but these proteins of m RNA increased significantly in SAH group and SAH+Atorvastatin group than the sham group(P<0.01). The m RNA expressions of v WF and TM were higher in the SAH group than SAH+Atorvastatin group(P<0.01). Immunohistochemical study showed that positive of v WF and TM were mainly located the cerebral vascular endothelial cells with little expression. SAH group and SAH+Atorvastatin group had a higher positive rate than Sham group on v WF and TM(P<0.01). In SAH+Atorvastatin group, the positive of v WF and TM in this study was significant decreased(P<0.01). We also found the ratio of basilar artery inner perimeter to vessel wall thickness(T) was significant decreased in SAH and SAH+Atorvastatin group(P<0.01). In SAH+Atorvastatin group, the T was significant higher than SAH group(P<0.01).Conclusions: 1. We found vasospasm and self-regulation dysfunction on vascular endothelial cells at early time after SAH; 2. Post-SAH Atorvastatin treatment can protect the vascular endothelial cells and reduce the vasospasm significantly; 3. The protective mechanisms of vascular endothelial cells might be Atorvastatin that it can decrease the content of v WF and TM.