| Objectives:Intracranial aneurysm(IA)is an abnormal bulge occurring in the wall of the intracranial arteries.The incidence of intracranial aneurysm(IA)is 9% ~ 15%,which is the main cause of subarachnoid hemorrhage.Besides,part of the aneurysm can produce mass effect or arterial spasm and embolism.As the intracranial aneurysm before the rupture of no obvious clinical symptoms,with occult disease and rupture after the characteristics of high morbidity,it is harmful to human health as a major disease.The exploration and intervention of the pathogenesis of intracranial aneurysm is the focus of the present study.However,the pathogenesis of IA is still unclear,the current study found that hemodynamics in the formation of aneurysms played an important role.Hemodynamic changes can lead to vascular wall remodeling,reducing the ability of the vessel wall to withstand tension,which led to the formation of aneurysms.Among them,Wall Shall Stress(WSS)is considered as important factors in the initiation of aneurysm formation.Hemodynamic changes in the WSS stimulated vascular endothelial cells activation of Toll like receptor to enter the inflammatory pathway to trigger inflammatory response.Studies have shown that diammonium glycyrrhizinate(DG)has anti-inflammatory,anti-oxidation and anti-apoptotic effects,but whether DG can prevent the occurrence and development of aneurysm has not been studied.This paper explores the mechanism of aneurysm formation in simple fluid mechanics and the mechanism of action of DG on aneurysm formation in animal experiments.Methods:130 New Zealand white rabbits were randomly divided into four groups: normal control group(A group),non-intervention group(B group),NS-intervention group(C group),DG-intervention group(D group).According to the observation time,each group was divided into 4 subgroups(2w,4w,8w,16w).The normal control group did not do any operation.The animal model of intracranial aneurysm was made by bilateral carotid artery ligation.The rabbits were injected with diammonium glycyrrhizinate 20 mg from the first week after the model establishment.The NS-intervention group was injected with the same amount of NS.The intracranial blood flow velocity and diameter of the animals were compared by TCD and MRA.The hydrodynamic changes were compared between the groups.The morphological changes of the arterial blood vessels were observed by hematoxylin and eosin(HE)staining.Masson staining was used to observe the change of elastic layer in the vessel wall.EVG staining was used to observe the change of the elastic layer in the blood vessel wall of each group.The expressions of TLR-4,NF-κB,VCAM-1,BCL-2 were detected by immunohistochemistry.Western blot was used to detect the expression of these proteins.The mean values of the measured data were expressed by X,and the comparison of the number of samples,blood flow velocity,vascular caliber,wall shear stress,immunohistochemistry and western blot were all analyzed by one-way ANOVA.The variance homogeneity test was performed by Levene method If the variance is homogeneous using the LSD method,if the variance is not used by Kruskal-Wallis method,P <0.05 is statistically significant.SPSS19.0 was used for statistical analysis.Results:1.The average value of basilar artery blood flow velocity in group A was 29.560±1.598 cm/s,group B was(173.120±6.681、217.620±12.992、163.490±5.227、 131.170±6.808)cm / s,group C was(176.590±7.271 、 211.330±11.407 、 164.420±4.392 、 127.970±3.247)cm/s,and D group was(178.580±6.014 、 212.420±12.825、164.380±6.770、130.880±4.862)cm/s.There was no significant difference between group D and group C(P=0.826),group D and group B(P=0.975).There was significant difference between group A and group C(P=0.000).2.Basilar artery diameter average of group A was(0.835±0.059)mm,group B was(0.893±0.100,2.034±0.185、2.723±0.192、3.126±0.473)mm,C group were(0.882±0.057,1.923±0.125 、 2.747±0.146 、 3.073±0.124)mm,group D were(0.879±0.089,0.879±0.089 、 1.930±0.100 、 2.790±0.100 、 3.136±0.526)mm,respectively.There was no significant difference between group D and group C(P= 0.515),group D and group B(P=0.245).There was significant difference between group A and group C(F=21.215,P=0.000).3.The mean wall shear stress of the basilar artery in group A was(36.621±2.630)Pa,(153.190±19.988、247.597±21.274、122.737±13.268、95.562±1.524)Pa in group B,(167.015±13.828、235.850±7.501、130.124±14.001、94.312±1.482)Pa in group C and(161.07±19.837、218.435±25.587、142.590±18.630、94.726±3.167)Pa in group D respectively.There was no significant difference between group D and group C(P=0.626),group D and group B(P=0.751).There was significant difference between group A and other group(F=14.806,P= 0.000).4.The immunohistochemical expression of basal arterial wall: BCL2: group A:(33.638±2.688)%,group B:(943.812±3.319 、 31.285±1.152 、 17.350±1.345 、8.588±1.077)%,group C:(44.712±3.264 、 32.690±1.682 、 17.541±1.016 、8.686±1.197)%,group D:(35.206±3.406 、 39.620±3.437 、 32.838±1.531 、32.538±2.516)%.There was significant difference between group D and group C(P=0.000),group D and group B(P=0.000),and there was no significant difference between group D and group A(P=0.648);TLR-4: group A:(10.159±1.306)%,group B:(21.571±1.783 、 30.566±2.096 、 47.084±2.056 、 64.442±2.456)%,group C:(22.043±1.234 、 30.692±1.507 、 47.187±1.862 、 64.564±2.269)%,group D:(14.282±2.259 、 15.302±1.061 、 22.351±3.315 、 22.411±3.475)%.There was significant difference between group D and group C(P=0.000),group D and group B(P=0.000),and there was no significant difference between group D and group A(P=0.077);NF-κB: group A:(13.749±1.679)%,group B:(27.318±1.340 、39.356±1.960 、 46.140±2.469 、 60.443±2.711)%,group C:(27.369±1.659 、40.130±1.535 、 46.139±2.315 、 60.570±1.925)%,group D:(21.215±1.611 、25.240±2.514、27.240±3.214、32.815±2.379)%.There was significant difference between group D and group C(P=0.000),group D and group B(P=0.000)and group A(P=0.000),and there was no significant difference between group B and group C(P=0.916);VCAM1: group A:(11.840±2.240)%,group B:(28.467±1.864 、38.191±1.888 、 52.696±2.968 、 71.224±2.128)%,group C:(28.561±1.636 、38.726±2.036 、 52.966±2.467 、 71.813±2.524)%,group D:(19.298±3.523 、24.859±2.875、24.748±1.755、26.789±3.123)%.There was no significant difference between group D and group C(P=0.000),group D and group B(P=0.000)and group A(P=0.011).There was no significant difference between group B and group C(P=0.900).5.Western blot results: BCL2: group A:(0.377±0.024),group B:(0.454±0.030、0.318±0.010、0.225±0.030、0.117±0.004),group C:(0.478±0.027、0.317±0.003、0.266±0.026、0.118±0.014),group D:(0.387±0.045、0.429±0.008、0.447±0.034、0.430±0.006).There was no significant difference between group D and group A(P=0.508),group B and group C(P=0.718).There was significant difference between group D and group B(P=0.002),group D and group C(P=0.006).TLR-4: group A:(0.137±0.016),group B:(0.561±0.016 、 0.748±0.015 、 1.474±0.161 、1.727±0.109),group C:(0.566±0.011、0.737±0.024、1.507±0.065、1.777±0.065),group D:(0.160±0.007、0.335±0.012、0.362±0.015、0.470±0.014).There was no significant difference between group D and group A(P=0.477),group B and group C(P=0.911).There was significant difference between group D and group B(P = 0.000),group D and group C(P=0.000);NF-κB: group A:(0.037±0.016),group B:(0.419±0.022、0.750±0.005、0.963±0.076、1.277±0.049),group C:(0.453±0.028、0.738±0.017、0.943±0.010、1.311±0.140),group D:(0.091±0.005、0.262±0.023、0.363±0.015、0.376±0.010).There was no significant difference between group D and group A(P=0.185),group B and group C(P=0.935).There was significant difference between group D and group B(P=0.000),group D and group C(P=0.000);VCAM1: group A:(0.150±0.003),group B:(0.616±0.045 、 1.514±0.050 、 2.305±0.046 、2.837±0.120),group C:(0.616±0.045、1.547±0.005、2.251±0.104、2.771±0.064),group D:(0.228±0.004、0.333±0.017、0.777±0.058、0.705±0.043).There was no significant difference between group D and group A(P=0.428),group B and group C(P=0.941).There was significant difference between group D and group B(P=0.000),group D and group C(P=0.000).Conclusions:1.The use of bilateral common carotid artery ligation method to produce rabbit intracranial aneurysm model has a high success rate.After ligation,the basilar artery blood flow velocity and the diameter of the aneurysm and the shear stress of the basilar artery bifurcation were all increased.Vascular wall structure damage,endometrial integrity disappeared,the membrane elastic layer is weak until disappear.After the formation of aneurysm-like bulge,the WSS of the bulge decreased,the aneurysm’s neck is still subject to high-wall shear stress shock,further damage the integrity of the surrounding wall caused by tumor expansion.2.During the whole process of aneurysm’s formation,the expression of TLR-4 in the basilar artery was up-regulated and the expressions of NF-κB and VCAM-1 were up-regulated in the TLR-4-related inflammatory pathway,while the expression of BCL-2 was decreased.3.During the whole process of aneurysm’s formation,Diammonium glycyrrhizinate inhibits TLR-4 and its downstream NF-κB,VCAM-1 expression,and inhibits BCL-2 expression down-regulation to reduce cell apoptosis,thereby reducing the destruction of arterial wall structure.DG play an intervention in the role of aneurysm formation. |
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