Impact Of Ischemia On Dendritic Structures In Mice Of Different Age And Gender

Dendritic spines are the key structure which formed synaptic connections between cerebral neurons. Spines in the brain are very sensitive to pathological changes. The difference resistance to cerebral ischemia between spines in different age and gender groups after acute ischemia remains unclear. In th present study,4-month-old and1-moth-old mice were used to set up the photothrombotic model of cerebral ischemia in our experiment and the golgi-staining was used to investigate the changes of dendritic lengths, the numbers of branches and dendritic spine densities in cortical layer V pyramidal cells under physiological and pathological conditions.Our result shows that:under physiological condition, we discover that apical shaft dendritic length of4-month-old mice is longer than other dendritic length for comparison of neuronal structures in different ages mice, and the apical shaft dendritic branch number in4-month-old mice are more than others; And dendritic spines of1-month-old mice is higer than others. We find that dendritic spine density of female mouse is greater than males for comparison of neuronal structures in different gender mice. The dendrtic branch number in4-month-old mice is more than1-month-old mice. There is no significant difference between left and right brain in dendritic spines density of normal mouse. Under pathological condition, comparing different aged mice discover that there is no signicicant difference of dendritic length between4-month-old and1-month-mice. However, the density of dendritic spines in4-month-old mice is less than1-month-old mice. The dendritic branch number of apical shaft in4-month-old mice is more than1-month-old mice. But there is no significant difference between4-month-old and1-month-old mice in branch number of basilar dendrite. And density of spines in right hemisphere in1-month-old mice is lower than it in left hemisphere. Especially, the same happened in1-month-old female mice.The dendritic length, the density of spines and the branch number in stroke mouse are lower than the normal mouse. The dendritic length of apical shaft has a significant change between mice of different age after the stroke. Especially, density of spines and dendritic length in1-month-old mouse decrease significantly. So we can see that stroke can destroy the neuronal structure of surrouding the infarct area in cerebral cortex, and it showed that neuronal damage mainly in the dendritic length of apical shaft and density of spines in the dendritic basilar.In summary, the density of dendritic spines decrease with increasing age, but the dendrtic branch number increases with increasing age. Particularly, the dendritic length increases significantly in apical shaft dendrite. The density of spines in female mouse is greater significanly than the male mouse between different gender, however, there is not found significantly difference of dendritic branch number and dendritic length. To sduty changes of neuronal structure on stroke associated with among age, gender and ischemic stroke, it can be provied a reference about stroke which is diagnosed and treated effectively, and it is layed the foundation for the study of neuronal structure and function.