Effects Of Stilbene Glycosides On Cognitive Impairment In Diabetic Mice

Objective: To explore the improvement effect and mechanism of tetrahydroxy stilbene glycoside(TSG)on cognitive impairment in diabetic mice,and provide a new strategy for the treatment of diabetic cognitive impairment.Methods: Seventy male C57BL/6J mice were used for the experiments,10 mice were randomly selected as the normal control group(Con group),and the remaining60 mice were injected intraperitoneally with streptozotocin(STZ)40 mg/kg combined with high glucose Fatty diet to prepare diabetes model.Diabetic mice that were successfully modeled were randomly divided into 3 groups: DM group,DM+TSG40group,DM+TSG80 group,with 12 mice in each group.Mice in DM+TSG40 group and DM+TSG80 group were gavaged with TSG 40 mg/kg and 80 mg/kg,respectively,mice in Con group and DM group were gavaged with corresponding volume of normal saline,once a day,for 8 consecutive weeks.During the administration period,the mice in the Con group were fed with normal chow,and the mice in the other 3groups were fed with high-sugar and high-fat diets,and the mice in each group had free to drink water.During the experiment,the blood glucose and body weight of the mice were monitored weekly.Eight weeks after administration of TSG by gavage,Morris water maze and fear conditioning experiments were performed to evaluate the learning and memory ability of mice in each group.After the behavioral experiment,blood was collected from the eyeball,and the mice were sacrificed to obtain the hippocampus and cortical tissue in the brain.The morphological changes of brain tissue in each group were observed by HE staining.The activity of SOD and GSH-Px and the content of MDA and GSH were determined by biochemical kits.The protein expressions of SIRT1/NLRP3,Ca MK2?,ERK1/2,CREB and their phosphorylation level were detected by Western blotting.Results:(1)The weight of the mice in the DM group decreased significantly,and the blood glucose level increased significantly compared with the Con group;The weight of the mice in the DM+TSG groups increased,and blood glucose levels decreased compared with the DM group.(2)The results of the Mirros water maze showed that compared with the Con group,the escape latency of the DM group was prolonged,the residence time of the target quadrant and the number of crossing platforms were shortened(P<0.05);Compared with the DM group,the escape latency of each dose group of DM+TSG was shortenen,the residence time in the target quadrant and the number of crossing platforms were increased(P<0.05).(3)The results of the conditioned fear memory experiment showed that there was no significant difference in the percentage of freezing time among the groups during training;the percentage of freezing time in the DM group was significantly lower than that in the Con group at 3 h,24 h and 120 h after the training,while the percentage of freezing time in each dose of DM+TSG groups was higher than that in the DM group(P<0.05).(4)The results of HE staining of the hippocampus and prefrontal cortex showed that compared with the Con group,the number of neurons in the DM group decreased,the arrangement was disordered,and the cells appeared deformed and necrotic.Compared with the DM group,the number of normal neurons in the DM+TSG groups increased,arranged neatly,and improved in different degrees.(5)The results of oxidative stress-related indicators in mice plasma,hippocampus,and cortical tissues showed that compared with the Con group,SOD,GSH-PX activity,and GSH content in the DM group were significantly decreased(P<0.01),while the MDA content was significantly decreased(P<0.01).Compared with the DM group,the SOD,GSH-PX activity and GSH content in each dose of DM+TSG group were increased in different degrees(P<0.01 or 0.05),while the MDA content was decreased significantly(P<0.01).(6)The detection results of related proteins in the hippocampus showed that compared with the Con group,the expression of NLRP3 protein in the DM group was increased(P<0.05),while the expression of SIRT1 was decreased(P<0.05).The expression of NLRP3 protein in DM+TSG groups was decreased in different degrees,while the expression of SIRT1 protein in DM+TSG groups was increased(P<0.05).There was no significant difference in the total protein expressions of Ca MK2?,ERK1/2 and CREB among the groups,while the levels of p-Ca MK2?,p-ERK and p-CREB in the DM group were significantly decreased(P<0.01),the levels of p-Ca MK2?,p-ERK and p-CREB in the DM+TSG groups were decreased significantly(P<0.01 or 0.05).Conclusion: TSG can improve cognitive impairment in diabetic mice,which may be related to reducing oxidative stress damage,regulating SIRT1/NLRP3 signaling pathway,and promoting the phosphorylation of Ca MK2?,ERK1/2,and CREB.