The Study Of Curative Effect Of Rho Kinase Inhibitor (Y-27632) For Subarachnoid Hemorrhage In Rabbits

Background:subarachnoid hemorrhage is a critical disease in neurosurgery department which has manycharacters,such as high morbidity、high mortality、high disability rate and used to appear mostly in youngadults.In the early of the subarachnoid hemorrhage, hemoglobin blocks the subarachnoid space, in theterminal subarachnoid fibrous tissue hyperplasia leads to the formation of late complications hydrocephalus.After subarachnoid hemorrhage, at the bottom of the brain those cerebral artery which have large capacitylumen have secondary contracture, which can cause diffuse cerebral edema and delayed ischemicneurological damage, it is the leading cause of death and disability about SAH. Cerebral vasospasm (CVS)is one of the factors that can affect the prognosis of SAH, its mechanism is regulated by a variety of signaltransduction pathways, Rho kinase is included,and it plays an important role in the development of CVS.Objective:New Zealand white rabbits were used as the research objects in our study. Rho kinase inhibitor wasused in the early stage, cerebrospinal fluid levels of Rho was assayed by ELISA.The gross specimen、microstructure、swelling degree of brain tissue of the basilar artery of New Zealand white rabbits wasobserved.which can clarify the relationship between the application of Rho kinase inhibitor and theoccurrence and development of complications after SAH. It can also provide more reasonable therapymethods for those patients who suffered SAH.Method:1. Model building: After anaesthetizing the New Zealand white rabbits provided by the animalexperiment center of Zhengzhou University, we fixed them on simple frames, and then drew off1.5mlblood in the medial auricular artery. After having punctured through the cervico-occipital junctional zoneinto the cisterna magna, we injected the autologous arterial blood into subarachnoid cavity. If those rabbitsshowed any sign of neck rigidity、dysphoria or somnolence without breathe and heartbeat disorder anddeath, we supposed that model building was succeeded 2. Choose40New Zealand white rabbits which meet the inclusion criterior. Seperate them into2groups(experimental group and control group) at random, and20in each group..3. Rho kinase inhibitor Y-27632was given to the experimental group3mg/kg.d six times in one day,and calcium channel blocker nimodipine10mg/kg.d six times in one day.For the control group onlycalcium channel blocker nimodipine10mg/kg.d six times in one day. Draw off cerebrospinal fluid on thefirst、the third、the seventh、the tenth and the fourteenth days, and cerebrospinal fluid levels of Rho wasassayed by ELISA.Carotid chromatic ultrasonic examination was proformed on the first、the third、theseventh、the tenth and the fourteenth days to detect the vascular diameter and blood stream velocity changeso as to predict the degree of cerebral vascular spasm.14days later, take out the rabbits’ basilar arteries andcerebral tissue to observe the changs of shape、color and elasticity of gross specimen, and weight thecerebral tissue of each rabbit to compare the liquid water content of cerebral tissue in order to judge theswelling degree.Result:1. Cerebrospinal fluid levels of Rho was assayed by ELISA on the first、the third、the seventh、thefourteenth days, and results showed that in the the third、the seventh、the fourteenth days,the expression ofRho kinase of the experimental group was much less than the control group (p<0.05).2. Results of Carotid chromatic ultrasonic examination on the first、the third、the seventh、the tenth andthe fourteenth days showed that the vascular diameter of the experimental group was slightly longer thanthe control group(p＞0.05),and the blood stream velocity of the experimental group was slightly faster thanthe control group(p＞0.05),and there was no difference in statistical significience.3. After14days rabbits’ basilar arteries were taken out, the results were observed under microscope,inthe experimental group,the number of arterial intima complete muscle layer and outer layer elastic fiber ingood condition was18, the number of endometrial dot damage was2; in the control group,the number ofarterial intima complete muscle layer and outer layer elastic fiber in good condition was4, the number ofendometrial dot damage with hyperplasia of muscular hypertrophy was16. The condition of the vascular inthe experimental condition was obviously better than the control group(p<0.05).4. After14days rabbits’ cerebral tissue were taken out, in the control group, the number showed conglutination and fibrosis in the subarachnoid cavity was16, the number showed ventricle enlargementwas12; in the experimental group the number showed slightly fibrosis was6and the number showedventricle enlargement was3.Mean cerebral tissue of the control group was obviously heavier than theexperimental group, and under the observation of the microscope, that the swelling incidence rate of thecerebral tissue was obviously higher than the experimental group（p<0.05）. Under microscope in thecontrol group the number that occured necrosis in different degree of brain edema was17, and the numberthat occurred brain edema with focal point necrosis in the experimental was5Conclusion:1. The expression of Rho kinase in the cerebral spinal fluid after SAH was high,and it also participatesin the generation of cerebral vascular spasm, and the quantity of Rho kinase was in relation with the degreeof cerebral vascular spasm2. Rho kinase inhibitor (Y-27632) could improve the condition of vascular’s degeneration andreconstruction caused by acute cerebral vascular spasm after SAH, which provided clinical evidence for theprevention and therapy of acute cerebral vascular spastic injury in neurosurgery department..3. Rho kinase inhibitor (Y-27632) could prevent the fibrosis of the arachnoid granualations andsubarachnoid cavitys, and also could prevent the occurrence of chronic hydrocephalus after SAH.