Relation Of The Research About The Medicine Interferation Of Plasma BNP And ET-1 With The Symptomatic Cerebral Vasospasm After Subarachnoid Hemorrhage In Model Rabbits

Objective To observe the effection of Nimodipine on plasma brain natriuretic peptide(BNP)and endothelin-1(ET-1)levels in cerebral vasospasm after subarachnoid hemorrhage. And to investigate it's mechanism in cerebral vasospasm.Methods The method of injecting autologous blood into the cisterna magna twice was adopted to make the model of cerebral vasospasm after Subarachnoid hemorrhage. The SAH rabbits were randomly divided into two groups (n=20 in each):Group A(SAH) was served as controls ; in Group B(SAH + Nimodipine )Nimodipine was as intravenously injected daily till the 14 day.The expression of BNP and ET-1 in peripheral blood was measured by enzyme-linked immunoassay and radio- immunoassay,and the blood flow velocity of basilar artery were measured by transcranial Doppler(TCD)on the preoperative 1 day and the postoperative 1, 4, 7, 11 and 14 day (day1, 4, 7, 11, 14).Results Food intake and neurological symptoms significantly decreased in the SAH group rabbits; however, ND group food intake and the symptysoms milder decreased than SAH group (P<0.05). SAH group in the day1 the blood flow velocity of basilar artery began to accelerate (P< 0.05), day4～day7 reached the peak (P<0.01), then gradually decreased; ND group the variational trends of blood flow velocity of basilar artery is consistent with SAH group, but the numerus of propotional time point was significantly lower than SAH group (P< 0.05). The concentration of BNP in the two groups showed significantly increasing on the day1(P<0.05), but the raised Concentr- ation of ET-1 was insignificance statistically(P>0.05). the Expression of BNP and ET-1 reached its peak was from the day4 to day7; and those levels were gradually declined with the duration of disease. After treatment of Nimodipine plasma BNP and ET-1 levels in group B were significantly lower than those in group A (P<0.01～0.05), but it was still significantly higher than the control group of pre-operation (P <0.05～0.01). The dynamic variational trend of the blood velocity of basilar artery of two groups of rabbits was basically in accordance with the expression of BNP and ET-1.Conclusion. The variance of basal artery flow rate of the SAH model rabbits was continuous monitored by applicating TCD , and TCD can indirectly reflect the status of CVS. Therefore, it can be used to evaluate the scope and extent of CVS. After SAH , BNP and ET-1 levels present dynamic change, theirs peak and time of readily appearing CVS were consistent. The degree of CVS was heavier, the levels BNP and ET-1 was higher. After SAH, plasma BNP and ET-1 content was to participate in pathological process of CVS. These findings support the concept that cerebral vasospasm after subarachnoid hemorhage in rabbits is partly dependent on expression and activity of BNP and ET-1. BNP and ET-1 are two types of vasoactive factors that their source is different and their function is antagonism each other. BNP and ET-1 play an important role in the pathological process CVS after SAH. The balance of reciprocal antagonist function of BNP and ET-1 was broken, which will cause vasomotor dysfunction , resulting in CVS. Nimodipine can reduce the level of plasma BNP and ET-1. the determination of plasma BNP and ET-1 level can help to determine whether appearing CVS, evaluate the degree of CVS , and predict disease prognosis.