| Objective:To investigate the effects of Losartan on the apoptosis and proliferation of vascular smooth muscle cells(VSMCS),including the changes of construction of vascular wall,and try to analyse the relationship between them. Methods:26 male Wistar rats,weighted from 0.23-0.25kg,were divided randomly as the control group(n=13)and the Losartan group(n=13).With a reference to improved Fishman's method, 5F punture needle was used to puncture the rat's left carotid artery after blood being stopped both ends.Then nitride gas was made to pass the lumen for 5 minutes in order to make the endothelial cells injured.The rats were fed up with standard food after operation.Then 4 rats of each group were killed randomly on the 3rd,the 7thand the 14th dayafter operation.then Losartan group was poured into stomach by Losartan 3mg disoved into 3ml saline.Control group was poured into stomach by the same amount of saline.TUNEL(terminal deoxynucleotidyl tranferase mediated dUTP nick endlabeling) was used to find apoptosis VSMCS.PCNA(proliferating cellnuclear antigen)was used to find proliferating VSMCS.With HE staining and computer analysis of pathological graph,we caculated the area of vascular walls,diameter of luminal and thickness of the vascular walls.Then we counted the positiveVSMCS through computer analysis system.Data were analized by STATA 1.4 software,and expressed as mean±SD,analyzed by one factor ANOVA to determine significannce between groups.Significance was established at p<0.05,most significance was established at p<0.01. Results:Most rats were healthy during the test.Two rats were died during the operation for losing blood.Each group has one.Another rat has died during fed up,which belongs to control group.So there were 23 rats alive at the end of the test(12 in Losartan group,11in control group). The apoptosis rates of VSMCS were increased since 3 days after operation in both groups.The Losartan group was (8.90±1.84)(%),while control group was (7.40±1.20)(%),There was no significance difference between the two groups.The VSMCS apoptosis rates went on increasing in the following days and got to the peak at 7 days after operation.The Losartan group was (47.59±3.17)(%),while the control group was (29.70±4.30)(%).The VSMCS apoptosis rate of Losartan group was hihger than the control group and the difference was significant.(p<0.01).At the last stage of the test,VSMCS apoptosis rate began to decrease.The Losartan group was (22.90±2.20)(%)on the 14days after operation.It was hihger than the control group (12.8±2.90)(%),The difference was significant(p<0.05).The positive PCNA VSMCS coulde be found on the 3 days after operation.The Losartan group was (10.90±1.50)(%).The control group was (11.4±1.20)(%).There was no significant difference between the two groups.On the 7 days after operation,the Losartan group was (28.98±2.90)(%) and the control group was (42.10±6.60)(%).There was significant difference between the two groups(p<0.05).On the 14 days after operation,the Losartan group was (24.10±3.12)(%),while the control group was (46.30±4.90)(%).There was significant difference between the two groups(p<0.05).The HE staining slice was used to be analysed by computer analysing system.We calculated the average area of vascular wall,luminal diameter and the thickness of the vascular.The average area of vascular wall of Losartan group was (0.242±0.042)(mm2),while the control group was (0.310±0.082)(mm2).There was significant difference between the two groups.(p<0.05).The luminal diameter in Losartan group was (818.37±72.05)(um),while the control group was (716.94±120.35)(um).The difference between the two groups was significant(p<0.05).The thickness of the vascular wall was (149.63±24.70)(um) in Losartan group and was (163.54±43.42)(um) in control group.There was significant difference between the two groups.(p<0.05).Conclusions:Losartan can elevate VSMCS apoptosis rate in vascular injuring model in rats and inhibit VSMCS proliferating rate.Maybe thr...
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