| Part I: Effects of hemodynamic changes on the expression ofmicro RNA – 143 Objective: The aim of this study was to investigate the effect of hemodynamic changes on the expression of micro RNA-143 by establishing different hemodynamic models,and to provide clues for exploring the pathogenesis of intracranial aneurysms and finding potential drug therapy.Methods:90 SD rats were randomly subjected to four groups: the experimental group A(n = 24),the experimental group B(n = 24),the experimental group C(n =24)and the control group(n = 18),.Three different hemodynamics models were established by microsurgery: group A: ligation of left common carotid artery and occipital artery,left wing jaw artery and right common carotid artery;group B : ligation of left common carotid artery,occipital artery and right common carotid artery;group C: ligation of the right common carotid artery.The blood flow velocity of the left carotid artery in the left side of the model was determined by color Doppler ultrasonography before modeling,1 day after modeling,1 month after modeling and 3 month after modeling.The left common carotid artery samples were taken from each group 1 day after modeling,1 month after modeling,and 3 months after modeling.After the specimens were taken out,they were placed in RNALater to avoid RNA Degradation.The expression of mi R-143 in the left common carotid artery was measured by Realtime-PCR technique at different time points.Results: Group A: The left common carotid artery flow rate one day after surgery was significantly lower than that before surgery(p <0.001),1 month after surgery was higher than 1 day after surgery(p = 0.027),There was no significant difference between 3 months and 1 month after operation.Mi R-143 of the left common carotid artery decreased at 1 day after operation compared with the control group(p = 0.005),1 month after surgery was higher than 1 day after surgery(p=0.04),3 month after surgery was lower than 1 month after surgery(p=0.003).Group B: The left common carotid artery flow rate one day after surgery was lower than that before surgery(p <0.001),1 month after surgery was higher than 1 day after surgery(p = 0.009),There was no significant difference between 3 months and 1 month after operation.Mi R-143 of the left common carotid artery decreased at 1 day after operation compared with the control group(p = 0.001),1 month after surgery was higher than 1 day after surgery(p=0.02),3 month after surgery was lower than 1 month after surgery(p=0.01).Group C: There was no significant difference in the left common carotid artery velocity between 1 day after operation and before operation,1 month after surgery was higher than 1 day after surgery(p = 0.009),There was no significant difference between 3 months and 1 month after operation.There was no significant difference in mi R-143 of the left common carotid artery between 1 day after operation and the control group,1 month after surgery was higher than 1 day after surgery(p=0.01),3 month after surgery was lower than 1 month after surgery(p=0.001).At the same time point,the left common carotid artery blood flow velocity of group A,B and C are different(p<0.05).Realtime-PCR results show that one day after operation: the expression of mi R-143 in the left common carotid artery of the rats of group A,B and C was statistically analyzed,the results show that group A <group B < group C(p<0.05);one month after modeling: the expression of mi R-143 in the left common carotid artery of the rats of group A,B and C was statistically analyzed,the results show that group A <group B < group C(p<0.05);three month after modeling: the expression of mi R-143 in the left common carotid artery of the rats of group A,B and C was statistically analyzed,the results show that group A <group B < group C(p<0.05).Conclusion: Ligation of rat carotid blood vessels,leaving only the left internal carotid artery to the intracranial blood supply,can make the left common carotid artery blood flow rate decreased the most significant.At the early stage of decreased blood flow,the expression of mi R-143 in the vessel wall also decreased.After the hemodynamic environment of the common carotid artery in rats,the vascular wall was self-adaptively changed,and the expression of mi R-143 in the wall was also changed..Part II: Effect of mi RNA-143 on intracranial aneurysmformation Objective: This study was designed to investigate the changes of mi R-143 and smooth muscle cell phenotype at different time points in the rat intracranial aneurysm model induced by hemodynamics.By continuous administration of simvastatin,investigating the effects of the drug on mi R-143,smooth muscle cell phenotype and aneurysm formation.Methods: 138 SD rats were randomly subjected to three groups: the experimental group(n = 48),the intervention group(n = 48),the blank group(n =42).The right common carotid artery,the left common carotid artery and the occipital artery and the left wing jaw artery were ligated by microsurgical technique to establish a simple hemodynamics-induced rat intracranial aneurysm model.Establishment of intervention group:the rats were administered with 20 mg / kg simvastatin one day before modeling,and the modeling process is same with aneurysm model group,one day to three months after modeling(after the ligation of blood vessels is completed,calculate the modeling time)rats were administered daily at 20 mg / kg simvastatin,weighed weekly and adjusted accordingly.Blank group without any intervention(n = 24).One day,one month and three month after modeling,six rats of each group were given to be sacrificed and the left ventricle was perfused with saline.The Willis circovirus was carefully removed into the Rinalater to avoid the degradation of RNA.The expression of mi R-143 in rat Willis loop was measured by Realtime-PCR technique at different time points.At the same time,6 rats in each group 1 day,1 month and 3 months after modeling were perfused with paraformaldehyde after perfusion of saline in the same way,and the acquired brain tissue was embedded and sliced.The expression of MMP-2,MMP-9 and a-SMA in the pre-traffic complex was detected by immunohistochemical staining.After 3 months of feeding,12 rats of each group were sacrificed and the Batson's # 17 mold was perfused by left ventricle.The rats were perfused in a 4 ? refrigerator,remove the brain specimens 24 hours later and etched it by 20% KOH solution for 12 hours.Each group of rat cerebrovascular specimens were got.The specimens of cerebral vascular perfusion were observed by scanning electron microscopy(TEM)and the aneurysm-like changes were evaluated.Aneurysm-like changes in the degree of four stages: stage 0: normal vascular cast;stage 1: vascular diameter uniform expansion,tortuous;stage 2: shallow baskigens elevation;stage 3: cystic aneurysm or local aneurysm-like expansion.Results:1 day after operation: there was no significant difference between the intervention group and the aneurysm group,the expression of mi R-143 in the Willis of the aneurysm group was higher than that in the blank group(p<0.001);MMP-2 and MMP-9:the intervention group was no significant difference compared with the aneurysm group,the aneurysm group was higher than the blank group(p <0.001);?-SMA: there was no significant difference between the aneurysm group ?intervention group and the blank group.1 month after operation: the expression of mi R-143 in the Willis of the intervention group was higher than that in the aneurysm group(p=0.001)and the aneurysm group was lower than that in the blank group(p=0.002).MMP-2 and MMP-9: the intervention group was lower than the aneurysm group(p < 0.001),the aneurysm group was higher than the blank group(p <0.001);?-SMA: the intervention group was higher than the aneurysm group(p<0.001),there was no significant difference in the aneurysm group compared with the blank group.3month after operation: the expression of mi R-143 in the Willis of the intervention group was higher than that in the aneurysm group(p=0.002)and the aneurysm group was lower than that in the blank group(p<0.001);MMP-2 and MMP-9: the intervention group was lower than the aneurysm group(p<0.001),the aneurysm group was higher than the blank group(p<0.001);?-SMA: there was no significant difference in the aneurysm group compared with the blank group,but the intervention group was higher than the aneurysm group(p<0.001).The results of scanning electron microscopy showed that the intervention group(stage 0 n=2,stage 1 n=6,stage 2 n=3,stage 3 n=1)was lower than that in the aneurysm group(p=0.045),but still significantly higher than the blank group(p<0.001).The incidence of aneurysm formation in the aneurysm group(stage 0 n=0,stage 1 n=3,stage 2 n=6,stage 3 n=3)was significantly higher than that in the blank group(p<0.001).there was no intracranial aneurysm formation in the blank group.Conclusion: In the process of aneurysm formation,intracranial Willis mi R-143 expression decreased,smooth muscle cell secretory expression increased.After simvastatin was administered,mi R-143 expression increased,smooth muscle cell secretory expression was inhibited,but contractile expression increased.Finally,the hemodynamic induced intracranial aneurysm generation was inhibited,but the simvastatin cannot completely inhibit the aneurysm formation. |
PDF Full Text Request