The change of expression of protease activated receptor-1 and tumor necrosis factor-α in the basilar artery of rats after subarachnoid hemorrhage

Objective To study different expression of protease activated receptor 1 (PAR1) and tumor necrosis factor alpha (TNF-α) in the rat cerebral vasospasm (CVS) model post subarachnoid hemorrhage (SAH),to discuss the relationship among PAR1,TNF-α,and CVS.Methods The rat cerebral vasospasm models of subarachnoid hemorrhage were made by the method that injection blood into the cisterna magna twice.Experimental groups:normal group,SAH 3 days group,SAH 5 days group,SAH 7 days group.Seven days after the first blood injection,the animals were transcardially perfused with 4％ paraformaldehyde in deep anesthesia and the brain was removed for histological examination.Measure cross-sectional area of vascular changes by computer software; Detect expression level of PAR1 and TNF-α by immunohistochemistry.Results SAH model animals' basal artery cross-sectional area was smaller than normal group,as time goes by spasm degree aggravating,the expression level of PAR1 and TNF alpha in SAH 3 d,SAH 5 d and SAH 7 d group tended to increase gradually.Conclusion (1) SAH model was established successfully by injection of autologous blood into the cistern magna,CVS happened in the basilar artery,the wall thickening and the lumen narrowing significantly suggests that the model can be used for researching cerebrovascular disease after SAH; (2) The immunohistochemical detection shows that the expression level of PAR1 and TNF-α increases significantly in the basilar artery of models and has a positive correlation with the degree of CVS. Key words: Subarachnoid hemorrhage;  Cerebral vasospasm ;  Thrombin ;  Protease activated receptor 1 ;  Tumor necrosis factor alpha