ABSTRACT
Objective To investigate the expressions of protein kinase B (PKB/Akt) and glycogen synthase kinasc-3β in the hippocampus in mice with vascular dementia (VaD) induced by repetitive bilateral common carotid artery occlusion.Methods Forty-eight healthy adult male C57B1/6 mice were randomly allocated into 3 group:normal group,sham operation group,and model group (n =16 in each group).A mouse VaD model was induced by intermittent blocking the bilateral common carotid artery for 3 times in the model group.The sham group only separated the bilateral common carotid artery,but did not block it.The normal group did not receive any treatment.The behavioral changes of the mice were observed using the water maze and step-down tests at 4 weeks after procedure.HE staining was used to observe the histopathological changes of hippocampal tissue.The Western blotting was used to detect the expressions of Akt,p-Akt (Ser473),GSK3β and p-GSK3β (Ser9) proteins.Results In the water maze test,the time of swimming the entire distance was prolonged at the learning stage and memory stage (learning stage:F =19.389,P ＜0.05; memory stage:F =27.929,P ＜ 0.05),the number of errors increased (learning stage:F =7.228,P ＜ 0.05; memory stage:F =21.189,P＜0.05) in the model group.In the step-down test,the response time was prolonged (F=19.162,P ＜0.05) at learning stage and the number of errors increased (F =6.562,P ＜ 0.05),the latency time was shortened (F=10.634,P＜0.05) and the number of errors increased (F=12.890,P＜0.05) in the model group.At the same time,HE staining showed the reduction of neurons and the proliferation of glial cells in the hippocampal CA1 region in the model group; p-Akt (Ser473) (F=37.849,P＜0.05) and p-GSK3β (Ser9)(F =67.725,P ＜0.05) protein expressions were up-regulated significantly (F =37.849,P ＜0.05; F =67.725,P＜0.05) at 4 weeks after procedure compared to those in the sham operation group,while there were no significant differences in Akt (F =1.004,P ＞0.05) and GSK3β(F =0.329,P ＞0.05) total protein expressions among all groups.Conclusions The repetitive bilateral common carotid artery occlusion may result in learning and memory impairment and severe damage in the hippocampus in mice.The Akt and GSK3β expressions may be involved in the mechanism of VaD.
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Objective To study the vulnerability of astrocytes bearing mutant SOD1 under the oxidative stress.Methods The cytotoxicity of the serum deprived astrocytes was measured by MTT.The level of ROS was shown by fluorescence of DCF through confocal microscopy.The expression of Nrf2,HO1 and NQO1 in the different cells was detected by Western blot.Results The level of cellular toxicity was higher in the astrocytes bearing mutant SOD1 exposed to the oxidative stress than the astrocytes hearing wild type SOD1.In the astrocytes bearing mutant SOD1,the expression of Nrf2,HO1 and NQO1 decreased.In the presence of mutant SOD1,an unexpected 44 per-cent decrease of Nrf2 was detected.This was associated with a decreases in multiple downstream phase Ⅱ detoxif-ying enzymes and antioxidant enzymes,known as NQO1 and HO1.Furthermore,our results showed that the ex-pression of NQO1 increased 1.5 and 2.5-fold by EGCG at 5 and 10 μmol/L.EGCG also elevated the expression of total Nrf2.Confocal microscopy showed that EGCG caused Nrf2 translocation from the cytoplasm to the nucleus.Conclusion Decrease in Nrf2 expression is the mechanism to explain the vulnerability of astrocytes bearing mutant SOD1 and EGCG strengthened antioxidation function by upregulating the activity of Nrf2.
ABSTRACT
@#Objective To investigate the apoptosis of neuron surrounding the hematoma in intracerebral hemorrhage(ICH)rats.Methods 64 male SD rats were randomly divided into two groups,trial group(ICH,n=56)and control group(sham operated,n=8).The brains of the rats were removed 6 h,12 h,24 h,48 h,72 h,7 d,14 d after ICH.Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-bioti in situ nick end-labeling(TUNEL)was used to detect deoxyribonucleic acid(DNA)fragmentation.The activation of caspase-3 was measured with immunohistochemistery.The electron microscope were used to observe histological changes surrounding the hematoma.Results Under transmission electronic microscope,shrunken neuron and glial cell with pre-apoptotic signs of intensely stained cytoplasm and abnormally dense nucleus,swollen blood vessel were found.TUNEL-positive cells appeared in the periphery of the hematoma and increased from 6 h to 14 d after ICH.Little TUNEL-positive cells could be found in the control group.The change of the caspase-3-positive cells was similar to TUNEL,but the peak of caspase-3-positive cells was more early than that of TUNEL.Conclusion The apoptosis of neuron occurred surrounding the hematoma in ICH rats and it may related to caspase-3.