| Objective: To observe the changes of blood-brain barrier permeability and the effects of lateral ventricle subependymal zone (SVZ) neurogenesis of the mice after 60Co-γray whole brain irradiation.Methods: 120 mice were randomly divided into 4 groups: control group,5Gy-irradiated group (low dose irradiated group),15Gy-irradiated group (medium dose irradiated group) and 30Gy-irradiated group (large dose irradiated group). The ability of space memory ability was tested by Morris Water Maze respectively before irradiation and 1 week and 1 month after irradiation. After neurobehavioral test, randomly selected 5 mice in each group to intravenous injection of Evans Blue, by measuring the Evans Blue content in brain tissue to evaluate the blood-brain barrier permeability changes; randomly selected 7 mice in each group use the method of immunohistochemistry to observed 5-bromodeoxyuridine (BrdU) positive cells number to evaluate of neurogenesis in SVZ; meanwhile randomly selected 3 for observed the changes of blood-brain barrier in SVZ under transmission electron microscope.Result:①Compared with the control group, medium and large dose irradiated group mice's spatial memory ability were decreased (P<0.05).②1 week after irradiation, Evans Blue content in brain tissue of medium and large dose irradiated group were increased compared with the control group (P<0.05), in which large dose group increased more significantly (P<0.01); 1 month after irradiation, in addition to large dose group Evans Blue content in brain tissue were more than the control group, other groups did not change significantly (P>0.05).③1 week after irradiation, the number of BrdU+ cells in SVZ in medium and large dose irradiated group were significantly decreased compared with the control group (P<0.01); 1 month after irradiation, BrdU+ cells in medium dose irradiated group had no difference (P>0.05), but in the large dose irradiated group is still significantly decreased (P<0.01).④Compared with the control group, pinocytotic vesicle of endothelium in low dose irradiated group were increased 1 week after irradiated. Vascular endothelium became thinner and irregular, bright zone appeared around the basement membrane in medium dose irradiated group. In large dose irradiated group, capillary vessels was irregular and bright zone could be found around the basement membranet. But 1 month after irradiation, there were no difference with the control group in low dose irradiation group; bright zone still around the basement membrane in medium dose irradiated group while the BBB of the large dose irradiated group became worse: nuclear pyknosis, capillary endothelial fracture, tight junctions between endothelial cells destroyed.Conclusion:①Medium and large doses of 60Co-γray whole brain irradiation prohibited the neurogenesis in SVZ.②Medium and large doses of 60Co-γray whole brain irradiation injury BBB, which further prohibited the neurogenesis in SVZ。...
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