Environmental Enrichment Improves Irradiation-Induced Cognitive Dysfunction

[Objective]Following a cognitive dysfunction mice model induced by ionizing irradiation,intervened with environmental enrichment,to explore the protective effect of Environmental enrichment on cognitive dysfunction and its underlying mechanism.[Methods]（1）Animal grouping:36 healthy adult female Kunming mice were randomly divided into control group,radiation group（IR）and radiation Environmental enrichment group（IR EE）.（2）Model building:The mice in IR group and IR+EE group were irradiated with ¹³⁷Cs rays at an absorbed dose of 4.0 Gy.Mice in the IR+EE group were housed in EE for35 d following irradiation;（3）Behavioral detecting:The object recognition task was used to evaluate the cognitive function of mice;（4）Biochemical detecting:the expression of the neurogenesis marker doublecortin（DCX）,and phosphorylated cAMP response element-binding protein（p-CREB）were detected by using immunohistochemical staining;The expression of cyclic AMP response element-binding protein（CREB）and Phosphorylated cyclic AMP response element-binding protein（p-CREB）proteins in hippocampus was assayed by using western blotting.[Results]（1）Experimental results of the object recognition task.Compared with the control group,the irradiation group had a low discrimination ratio in the object recognition task（P<0.05）.Compared with the IR group,the IR+EE group had an enhanced discrimination ratio（P<0.05）.（2）Expression of DCX in mouse hippocampus.Compared with the control group,the number of DCX positive cells in the hippocampus of the IR group was significantly decreased（P<0.05）.Compared with the IR group,the number of DCX positive cells in the hippocampus of the IR EE group was significantly increased（P<0.05）.（3）Expression of CREB and p-CREB in hippocampus of mice.The results of western blotting and immunohistochemical staining showed that compared with the control group,the expression of CREB in hippocampus was not significantly decreased after ionizing radiation,while the expression of p-CREB protein and p-CREB/CREB were down-regulated（P<0.05）.Compared with IR group,there was no difference in CREB protein expression between IR EE mice（P>0.05）,while p-CREB protein and p-CREB/CREB expression were up-regulated（P<0.05）.[Conclusion]1.Environmental enrichment can improve the cognitive dysfunction of mice induced by ionizing radiation.2.Environmental enrichment can improve hippocampal neurogenesis by activating the expression of CREB protein in the hippocampus and promoting,thereby improving radiation-induced cognitive dysfunction.