CT Perfusion Imaging Of Cerebral Microcirculatory Changes Following Subarachnoid Hemorrhage In Rabbits: Specific Role Of Endothelin-1 Receptor Antagonist

Objective: Cerebral vasospasm may lead to delayed ischemic neurological deficits following subarachnoid hemorrhage(SAH).Endothelin(ET-1)is an important factor participating in cerebral vasospasm underlying SAH.We used a specific endothelin receptor antagonist,BQ123 to assess the specific role of endothelin-1 receptor antagonist in cerebral vasospasm in a rabbit model of SAH by examining plasma ET-1 levels and the principal CT perfusion(CTP)parameters pertinent to the hemodynamic status of microcirculation following SAH.Materials and Methods :102 male New Zealand white rabbits were divided into control,SAH and SAH+BQ123 intervention group(BQ123 group).Rabbit SAH model was established by double hemorrhage injection of autologous blood into the cisterna magna;Aquilion ONE was used to collect cerebral blood flow(CBF),cerebral blood volume(CBV),and mean transit time(MTT)which were used to evaluate cerebral microcirculation hemodynamics;Elisa was used to assess plasma ET-1 levels.Data were collected on days 1,4,7 and 14 following SAH,respectively.Results:Compared with the control group,CBF was significantly decreased(P<0.05),MTT was significantly prolonged(P<0.05),and CBV was not significantly changed in the SAH group.Among them,CBF decreased on the 4th day and reached the lowest value on the 7th day;MTT began to rise on the 4th day and reached the peak on the 7th day.Compared with SAH group,BQ123 group significantly improved microcirculation blood perfusion on the 1st and 4th day,CBF was significantly increased(P<0.05),On the first day of BQ123 group,the MTT value of temporal lobe was significantly higher than that of frontal lobe and occipital lobe(P<0.05).On the fourth day,CBV value was significantly higher in the occipital lobe than in frontal lobe and temporal lobe(P<0.05).The plasma ET-1 level in the BQ123 group was significantly higher than that in the SAH on the 1st and 4th day(P<0.05).There was no significant difference on the 7th and 14 th day.In addition,the inflammatory infiltration of brain tissues in rabbits treated with BQ123 post-SAH was significantly reduced compared with SAH group.Conclusion:CTP can quantify the therapeutic effect of BQ123 after SAH;Selective blockade of ET-1 endothelin receptor,BQ123 significantly improved microcirculatory perfusion along with a reduction in resultant vasogenic inflammatory responses.The effect of BQ123 on the cerebral microcirculation was lobe dependent.