GRIK2过表达对七氟烷暴露幼鼠空间学习和记忆能力的改善作用及其机制OA

Objective:To discuss the improvement effect of overexpressing kainate receptor subunit(GluK)2 on the spatial learning and memory abilities of juvenile mice exposed to sevoflurane(Sevo),and to clarify its possible molecular mechanism.Methods:A total of 44 C57BL/6J neonatal mice were randomly divided into control group,Sevo group,Sevo+OE-NC group(virus empty vector group),and Sevo+OE-GRIK2 group(GRIK2 overexpression group).There were 3 mice in each group for molecular experiments and 8 mice in each group for behavioral experiments.Morris water maze test was used to detect the escape latency,the residence time in the target quadrant,and the number of platform crossings of the juvenile mice in various groups.The Sevo anesthesia model was established in the mice on postnatal day 6(P6);immunofluorescence method was used to observe the expression of GluK2 protein and the virus transfection situation in hippocampus tissue of the juvenile mice in various groups;Western blotting method was used to detect the expression levels of sodium-potassium-chloride cotransporter 1(NKCC1),potassium-chloride cotransporter 2(KCC2),and GluK2 proteins in hippocampus tissue of the juvenile mice in various groups.Results:The Morris water maze test results showed that on days 3,4,and 5 of training,compared with control group,the escape latency of the young mice in Sevo group was significantly prolonged(P＜0.05 or P＜0.01).The Morris water maze test results showed that on days 4 and 5 of training,compared with Sevo group,the escape latency of the young mice in Sevo+OE-GRIK2 group was significantly shortened(P＜0.05 or P＜0.01);compared with Sevo+OE-NC group,the escape latency of the young mice in Sevo+OE-GRIK2 group was significantly shortened(P＜0.05 or P＜0.01).The Morris water maze test results showed that compared with control group,the residence time in the target quadrant of the young mice in Sevo group was decreased(P＜0.05);compared with Sevo group,the residence time in the target quadrant of the young mice in Sevo+OE-GRIK2 group was increased(P＜0.01);compared with Sevo+OE-NC group,the residence time in the target quadrant of the young mice in Sevo+OE-GRIK2 group was increased(P＜0.01).The Morris water maze test results showed that compared with control group,the number of platform crossings of the young mice in Sevo group was decreased(P＜0.001);compared with Sevo group,the number of platform crossings of the young mice in Sevo+OE-GRIK2 group was increased(P＜0.001);compared with Sevo+OE-NC group,the number of platform crossings of the young mice in Sevo+OE-GRIK2 group was increased(P＜0.001).The immunofluorescence results showed that compared with control group,the expression level of GluK2 protein in hippocampus tissue of the young mice in Sevo group was decreased(P＜0.05);compared with Sevo group,the expression level of GluK2 protein in hippocampus tissue of the young mice in Sevo+OE-GRIK2 group was increased(P＜0.01);compared with Sevo+OE-NC group,the expression level of GluK2 protein in hippocampus tissue of the young mice in Sevo+OE-GRIK2 group was increased(P＜0.01).The Western blotting results showed that compared with control group,the expression levels of KCC2 and GluK2 proteins in hippocampus tissue of the young mice in Sevo group were decreased(P＜0.05 or P＜0.01),and the NKCC1/KCC2 ratio was increased(P＜0.05);compared with Sevo group,the expression levels of KCC2 and GluK2 proteins in hippocampus tissue of the young mice in Sevo+OE-GRIK2 group were increased(P＜0.001),and the NKCC1/KCC2 ratio was decreased(P＜0.05);compared with Sevo+OE-NC group,the expression levels of KCC2 and GluK2 proteins in hippocampus tissue of the young mice in Sevo+OE-GRIK2 group were increased(P＜0.001),and the NKCC1/KCC2 ratio was decreased(P＜0.05).Conclusion:Overexpression of GRIK2 upregulates the expression levels of GluK2 and KCC2 proteins in hippocampus tissue of Sevo-exposed juvenile mice and improves the spatial learning and memory abilities of juvenile mice,and its mechanism may be related to reducing the NKCC1/KCC2 ratio in hippocampus tissue.