Study On The Protective Mechanism Of Troxerutin On The Neurovascular Unit After Ischemic Stroke In Rats

Objective To observe the effect of Troxerutin and Cerebrprotein Hydrolysate on the neurovascular unit after middle cerebral artery occlusion(MCAO)in rats,and to explore its possible mechanism.Method 120 male SD rats were randomly divided into 3 groups by random number table: sham operation group(SHAM group,n=40),MCAO group(n=40),MCAO+ Troxerutin treatment group(n=40).In MCAO group,according to He Min’s modified method of MCAO model of permanent.MCAO group was injected Troxerutin and Cerebrprotein Hydrolysate,3ml/kg,three times per day,for 3 days after MCAO by intraperitoneal,the MCAO group was gave the same dose of saline.After MCAO 1day,3days,7days,each group random selected 10 rats,and used the modified neurological severity score(m NSS)to evaluate the degree of injury of nerve function.After MCAO 3days,each group selected 5 rats,used 7.0 T MRI scans,T2 and ASL sequence to evaluate the infarct volume and blood flow changes in infarction area.Each group selected 10 rats,used nissl staining and immunofluorescence to evaluate the survival rate and shape of neuron,the expression of microglia,astrocyte,endothelial cells and tight junction of blood brain barrier.Each group selected 10 rats,used western blot and ELISA to evaluate the expression of n NOS,i NOS,e NOS,NO and 3-NT.Each group selected 5 rats,used transmission electron microscopy to evaluate the tight junction of ischemic penumbra.Result MCAO leads to severe neurological deficits.After MCAO 3days,7days,14 days,MCAO+ troxerutin treatment group compared with the MCAO group m NSS scores were significantly decreased.After MCAO 3days,the T2 sequence of MRI showed the region of the middle cerebral artery blood supply is high signal and the ASL sequence showed the blood flow signals decreased,MCAO+ troxerutin group compared with the MCAO group,T2 sequence showed the infarct volume was significantly decreased,ASL sequence showed the blood flow signal was significantly increased.Nissl staining showed that the survival rate decreased and vacuolation after MCAO.MCAO+ troxerutin group compared with MCAO group these changes were significantly reduced.After MCAO 3 days,immunofluorescence staining showed that the marker of astrocytes and microglia was increased and the marker of endothelial cells and tight junction was decreased,MCAO+troxerutin group compared with MCAO group these changes was decreased.Western blot showed that n NOS,i NOS,e NOS monomer and 3-NT was increased after MCAO,while these molecule was significantly decreased when troxerutin treated.ELISA showed that the content of NO decreased after MCAO,MCAO+ troxerutin group compared with MCAO group the content of NO was significantly increased.Conclusion Troxerutin and Cerebrprotein Hydrolysate can protect the neurovascular unit of rats after MCAO by decreasing the expression of n NOS,i NOS and e NOS monomer,reducing the production of 3-NT,increasing the content of NO.