| Objective:Our purpose was to establish vascular dementia(VD)model in rats.Methods:①The VD model was established by the method of improved four-vessel occlusion.Abilities to learning and memory of rats were tested by using the localization sailing test and space pilot test with Morris water maze after four weeks breeding.②The pathological changes of rats ' hippocampus tissue of every group were observed by light microscope after stained by hematoxylin eosin(HE).Results:①The analysis of conditions among the folder times of experimental rats' carotid artery:After 4-week of modeling,the results of water maze showed that there was no statistically significant difference between the average latency of 1-minute group and 2-minute group(the survival rate of 100%,the rate of model success of 0).In 3-minute group,four rats had survived,but only one rat had mode(the survival rate of 100%,the rate of model success of 25%).In 4-minute group,three rats had survived and mode(75 percent survival rate,the rate of model success of 75%),only one died(mortality rate of 25%).In 5-minute group,only one rat survived and mode(25 percent survival rate,the rate of model success of 25%),and three rats died(mortality rate 75%).②To compare the localization sailing test:After 4-week of modeling, significant differences in the latency from the second day to the forth day were found between VD group and sham operation group(P＜0.01).③To compare the space pilot test:During 120 seconds,the average lingering time at platform quadrant of VD group and sham operation group was 27.66±5.39s,56.66±7.97s respectively,accordingly,it was significantly different between VD group and sham operation group(P＜0.01).④The pathological changes of rats' hippocampus tissue of every group:Compared with sham operation group,the arrangement of the pyramidal neurons in CA1 region was sparse and tangled,and there were many cellular swelling,loss and pyknosis in VD group.The above-mentioned changes were not found in sham operation group.Conclusions:This study improved Pulsinelli's 4-Vessel occlusion method and worked out a model of best condition which was that the rat's vertebral arteries were electrocauterized and 72 hours later the carotid clasps that placed loosely around the common carotid arteries tightened for 4 minutes and then removed,repeating three times in total,each time interval was 1 hour.This model of vascular dementia is useful for studying vascular dementia.It can be used in basic experiment study with its good practicability and reliability.Objective:To establish a method of culture and expansion of rat bone marrow-derived mesenchymal stem cells(MSCs)in vitro.To identify and label the bone marrow-derived MSCs harvested in this study. Methods:To utilize the whole medulloculture plus digestion control for the separation,purification and serial subcultivation of mesenchymal stem cells(MSCs)from rat bone marrow.And the MSCs were identified by detecting their immunophenotype through flow cytometry and inducing their differentiation to bone.Results:①The highly purified bone marrow-derived MSCs of rats were harvested and the corpuscular activity was well keeping in this study.In vitro the bone marrow-derived MSCs were growed with adherence and exhibited a spindle-shaped fibroblastic morphology.②As flow cytometry showed,about 89.4%cells of MSCs were positive for CD44 and 99.2%cells of MSCs were positive for CD90,meanwhile,only 1.82%cells of MSCs were positive for CD34.After bone induction,alizarin Bordeaux S showed that the calcium nodus was positive.Conclusions:A feasible method for the separation,purification and proliferation of MSCs from rat bone marrow has been established.The cultured MSCs are active in high purity with stable biological character.The culture method combining the whole medulloculture and digestion control is simply performed in need of little condition,so it is one of the optimal methods for cell preparation and purification at present.The cultured cells were identified to be MSCs by flow cytometry and inducing their differentiation to bone. Objective:To study the praxiological and pathological changes of vascular dementia(VD)rats after transplantation of bone marrow-derived MSCs into hippocampus.Methods:The cultured cells were labeled with 5-bromo-2'- deoxyuridine (Brdu)and transplanted into hippocampus of adult VD rats(transplantation group),moreover,VD control group,medium control group and sham operation group were set up to control.After four-week breeding,abilities to space learning and memory of rats were tested by using the Morris water maze.The pathological changes of rats' hippocampus tissue of every group were observed by light microscope after stained by hematoxylin eosin(HE).Results:①To compare the localization sailing test:After 4-week transplantation of MSCs,significant differences in the latency from the second day to the forth day were found between VD control group and sham operation group(P＜0.01).In addition,there were statistically significant differences in the latency from the second day to the forth day between transplantation group and VD control group(P＜0.001)and the differences in the latency from the second day to the forth day between transplantation group and medium control group were also statistically significant(P＜0.001).But there were no statistically significant differences between medium control group and VD control group(P＞0.05).②To compare the space pilot test:During 120 seconds,the average lingering time at platform quadrant of VD control group,transplantation group,medium control group and sham operation group was 27.15±4.55s, 54.45±7.37s,28.64±2.21s,57.99±8.91 s respectively,accordingly,it was significantly different between VD control group and sham operation group(P＜0.01).Meanwhile,the differences between transplantation group and VD control group were statistically significant(P＜0.001)and it was also significantly different between transplantation group and medium control group (P＜0.001),but insignificantly different between the medium control group and VD control group(P＞0.05).③The pathological changes of rats ' hippocampus tissue of every group:Compared with VD control group,the pathologic impairments appeared in MSCs transplantation group were much better,the arrangement of the pyramidal neurons in CA1 region was more regular,the cellular swelling,loss and pyknosis were much better.But the changes between medium control group and VD control group were not significant.Conclusions:Transplantation of MSCs into hippocampus can improve the abilities to space learning and memory of VD rats,and provide certain protection for the nerve injury originated by interative cerebral ischemia.
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