血管性痴呆小鼠海马CA1区CalpainⅠ表达的变化

The expression of Calpain I in the hippocampal CA1 area of mice with vascular dementia

目的探讨脑缺血—再灌注后不同时期血管性痴呆(VD)小鼠海马CA1区病理改变及CalpainⅠ表达的变化。方法243只雄性昆明小鼠随机分为假手术组(99只)和模型组(144只),VD动物模型采用双侧颈总动脉反复缺血—再灌注合并尾端放血的方法制备;分别于造模后第4周、6周和8周测试小鼠的学习和记忆成绩,HE染色观察小鼠海马CA1区正常神经元计数,免疫组化方法观察CalpainⅠ的表达。结果造模后4周、6周和8周时模型组小鼠的学习、记忆成绩均明显劣于假手术组小鼠(P<0.05)。假手术组海马CA1区单位面积正常神经元计数分别为(102±15)个、(108±11)个和(101±12)个;模型组分别为(65±19)个、(21±3)个和(50±11)个,较假手术组均显著降低(P<0.05),其中以造模后6周损害最严重,较模型组造模后4、8周时也显著减少(P<0.05)。假手术组造模后4周、6周和8周时小鼠海马CA1区CalpainⅠ的平均OD值分别是0.030±0.003、0.031±0.003和0.029±0.003;模型组CalpainⅠ的平均OD值分别是0.099±0.009、0.121±0.010和0.115±0.010,较假手术组均显著增高(P<0.05),尤以术后6周时增高明显。结论脑缺血—再灌注6周时海马CA1区神经元损害最严重,CalpainⅠ参与了脑缺血—再灌注后小鼠VD的发生。

Objective To investigate the change of neuronal pathology and the expression of Calpain I in the hippocampus CAI area of mice with vascular dementia（VD） following cerebral ischemia and reperfusion. Methods There were 243 male Kunming mice were randomly divided into two groups： the sham-operated group （ n = 99） and the model group （ n = 144）. The model of VD was induced by three times of transient ischemia-reperfusion of bilate ral common carotid arteries, combined with tail bloodletting. The behavioral tests were done respectively at 4th,6th and 8th week post surgery. The neuronal pathological changes of the hippocampus were observed with HE staining. The expression of Calpain 1 in hippocampus CA1 area were detected by immunohistochemistry staining. Results The lear ning and memory performance of model group were damaged significantly at 4th,6th and 8th week post surgery compared to sham-operated group（ P 〈 0.05）. The number of normal neuron at 4th,6th and 8th week post surgery were 102 ±15,108± 11 and 101 ± 12 in sham-operated group, while the number in model group were 65 ±19,21±3 and 50 ± 11 respectively, signifieantly lower than sham-operated group （ P 〈 0.05 ）. Among those, the most damaged group were 6th week post surgery,and the number of normal cell were lower than that of 4th and 8th week post surgery. （ P 〈 0.05 ）. The OD value of Calpain I in model group was 0. 099 ± 0. 009,0.121 ± 0. 010 and 0. 115 ± 0.010 respectively, higher than that of the sham-operated group which was 0. 030 ± 0. 003 ,0. 031 ± 0. 003 and 0. 029 ±0. 003, and there was a significant difference （ P 〈 0.05 ）, especially at time point 6th week post surgery. Conclusion It demonstrated that the most werious neuronal damage was occurred at 6th week post cerebral ischemia and reperfusion, and Calpain I was proved to be involved in the occurrence of VD.