| Objective: Morbidity of coronary atherosclerotic heart disease(coronary heart disease,CHD)has surged over time and become the top cause of death in developed countries in the west as the environment changes and quality of life has improved.In the Chinese population,the situation of a rising incidence of CHD seems similar.Since coronary artery bypass grafting(CABG)was invented,it has been universally recognized as an effective treat to CHD as proved by years' clinical application and statistics of follow-ups.Left internal thoracic artery,radial artery,right gastroepiploic artery,inferior epigastric artery and great saphenous vein are available choices for source of grafts.Considering selection of graft source is limited by time of operation,proneness to vasospasm and requirement of vascular diameter and length,the great saphenous vein is the most frequently chosen.However,when being harvested,great saphenous vein is vulnerable to damage caused by mechanical stretch or electric stimulus,often the efficacy is not satisfactory.Vascular endothelial cells(VECs)is a barrier layer and at the same time can produce and release many regulatory factors which can regulate vascular tension,anticoagulation and anti-inflammation.Meanwhile,evidence shows that slight changes in phenotype of VECs and function disorder can be observed ahead of morphological changes of atherosclerosis.Thus damage and disorder of VECs are believed to be the most critical factors in the occurrence,progression and exacerbation.Currently,during a CABG,the great saphenous vein is preserved in heptin-papaverine solution after harvesting.However,the preservative solution only can exert effects of anticoagulation and vasodilation which are less than sufficient in preserving VECs of the graft vessel.By incorporating ex vivo external jugular vein into carotid artery at the same side of rabbits,a model was established to mimic the clinical operation of CABG in the present study to observe and compare changes in morphology,ultrastructure and secretion functions to determine the preservative effect of different preservative solutions and provide laboratory evidence for selection of preservative solutions in clinical practice.Methods:1 30 New Zealand white rabbits which were met the conditions were randomly divided into 3 groups:the blank group(heparin saline group,n = 10)?the control group(papaverine heparin saline group,n = 10)and the experimental group(heparin diltiazem hydrochloride saline group,n =10).Bulid a model by simulating the process of vascular anastomosis in coronary artery bypass surgery.After the treatments and interventions such as rinsing and soaking by different preservation solution,the external carotid veins away from the bodies were divided into two sections named section A and section B.Section A was used to observe the recent changes of morphology under the transmission electron microscopy and light microscopy,and the fraction of coverage of the VECs was also measured and calculated.Section B was used to anastomose to common carotid artery.The content of PGI2 in the preservation solution of each group was measured with Elisa.A month later,the vein graft section B,anastomosed to common carotid artery,was taken to observe the changes of morphology under the electron microscopy and measure and calculate the fraction of coverage of the VECs.2 The obtained data analysis was performed with the statistical software SPSS13.0.The data of each group would be tested by normality test and f test.If the data is accord with normal distribution and homogeneity of variance,we will analyze the difference of the means of the two groups and the statistical significance by independent samples t tests.If the data is accord with normal distribution but not with the homogeneity of variance,then the degree of freedom will be revised.If the data does not fit the normal distribution,the nonparametric tests will be usable.The statistical significant standard was setat p < 0.05 in our tests.Results: Thirty rabbits were involved in this experiment and in the result analysis.None of the vein grafts of the three groups after operation was necrosis or block.(1)The results of the endothelial cell coverage in short-term light microscope showed that,the blank group scored 1.750 ± 0.312 ? the control group scored 1.700±0.405?and the experimental group scored 2.25± 0.264.There was no statistically significant difference between the blank group and the control group,and,the experimental group was obviously better than the other two groups(P < 0.05).(2)The results of the transmission electron microscopy showed that,VECs of the experimental group wrer less likely to fall off,and had relatively complete morphology,and their basement membranes were continuous,and they were closely connected to others.In contrast,the results were better than the other two groups.(3)The results of the ELISA showed that,the content of PGI2 in the blank group was 100.542±20.043pg/ml,in the control group was 105.777 ± 19.143pg/ml,in the experimental group was 128.049 ± 21.713pg/ml.There was no statistically significant difference between the blank group and the control group,and,the experimental group was obviously better than the other two groups(P < 0.05).(4)The results of the endothelial cell coverage in long-term light microscope showed that,the blank group scored 1.500±0.373?the control group scored1.575±0.290?and the experimental group scored 1.875±0.295.There was no statistically significant difference between the blank group and the control group,and,the experimental group was obviously better than the other two groups(P < 0.05).Conclusion:1 In this experiment,Diltiazem Hydrochloride Solution proved to have effective protection on VECs of autogenous vein grafts in rabbits.And it was conducive to the role of secrete bioactive substances of the VECs in grafted veins.2 In the protective effect on vein grafts,diltiazem hydrochloride solution is better than papaverine heparin saline or heparin saline.And the differencehas the statistically significant.The difference between the papaverine heparin saline and heparin saline has no statistically significant. |
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