| Objective: To investigate the changes of MLCK,NMDAR subunit NR2 B and Wnt/β-catenin pathway-related molecules in the hippocampal tissues of diabetic rats after oral administration of Polygonum multiflorum,and the changes of learning and memory function and ultrastructure of hippocampal neurons,the possible mechanism to improve diabetic encephalopathy was discussed.Methods: 1.Water maze test selected SD rats with the same level of cognitive function,randomly divided into control group(n=12),diabetic group(n=12),low-dose group of Polygonum multiflorum,(n=12),high-dose group of Polygonum multiflorum,(n=12),and insulin group(n=12).The latter four groups were intraperitoneally injected with streptozotocin to replicate the diabetes model.2.After the model was established,the insulin group was subcutaneously injected with 8U/kg of insulin twice a day,the low-dose group was intragastrically administered with 1g/kg of Polygonum multiflorum,and the high-dose group was administered with 2g/kg of Polygonum multiflorum,this experienced for a total of 8 weeks.3.During the intragastric and intraperitoneal injection,the fasting blood glucose of each group was monitored;after intragastric administration,the water maze was used to monitor the cognitive function of each group.the ultrastructural changes of hippocampal neurons in each group were observed by electron microscopy.The morphology of hippocampal tissue was observed by HE staining.the expressions of MLCK,NR2 B,p-GSK-3β,GSK-3β,β-catenin,p-β-catenin in hippocampus were detected by Western blot.and the expression of Wnt3 a protein in the hippocampal tissues of each group was detected by enzyme linked immunosorbent assay.Results: 1.Compared with the control group,the fasting blood glucose of the diabetic group increased significantly(P<0.01).Compared with the diabetic group,the fasting blood glucose level of the insulin group and the high-dose group of Polygonum multiflorum decreased significantly(P<0.01),and the effect of the high-dose group was more obvious than that in the low-dose group.2.Compared with the control group,the number of crossings in the diabetic model group were significantly reduced,and the escape latency was significantly prolonged(P<0.01).Compared with the diabetic group,the number of crossings increased in the high-dose group and the insulin group,and the escape latency was significantly shortened(P<0.01),while there was no significant difference between the low-dose group and the diabetic group(P>0.05).3.Compared with the control group,the expressions of MLCK and NR2 B in the diabetic group were significantly increased(P<0.05).Compared with the diabetic group,the expressions of MLCK and NR2 B in the high-dose group and the insulin group were decreased(P<0.05),and there was no significant difference between the low-dose group and the diabetes group(P>0.05).Compared with the control group,the expressions of β-catenin and p-GSK-3β in the diabetes group were significantly reduced,The expression of p-β-catenin were significantly increased(P<0.01).Compared with the diabetic group,the levels of β-catenin and p-GSK-3β in the high-dose group and the insulin group were significantly increased,The expression of p-β-catenin were decreased(P<0.05),and the difference between the low-dose group and the diabetic group was not significant(P>0.05),there was no significant difference in the expression of GSK-3β in the five groups(P>0.05).4.The results of electron microscopy showed that the mitochondrial enlargement was vacuolated in the neurons of the diabetic group,the nuclear and nuclear membranes were incomplete,and the number of neurons was significantly reduced.Compared with the diabetic group,the mitochondrial morphology,nuclear membrane integrity and the number of neurons in the neurons of the high-dose group and the insulin group were well,and the number of neurons was significantly increased in the high-dose group and the low-dose group.5.The results of HE staining showed that the hippocampal cell structure of the diabetic group was disordered,with edema in the cells and interstitium,and the cell structure was not complete.The cell edema disappeared in the high-dose group,and the structure was clear and the arrangement was regular,and the high-dose group was more obvious than the low-dose group.The hippocampal neurons in the insulin group were arranged in a regular pattern,and there was no significant difference between the insulin group and the control group.6.For the control group,the expression of wnt3 a in the hippocampus of the diabetic group was significantly decreased(P<0.05).for the diabetic group,the expression of wnt3 a in the hippocampus of the high-dose group and the insulin group increased(P<0.05),while the expression of wnt3 a was not significant between the lowdose group and the diabetic group.Conclusion: 1.preparation of Polygonum multiflorum by intragastric administration can improve hippocampal neuron structure and improve learning and memory ability in diabetic rats.2.The treatment of Polygonum multiflorum can down-regulate the expressions of MLCK and NR2 B in the hippocampus of diabetic rats,and also up-regulate the expression of Wnt/β-catenin signal pathway,there by improving the cognitive dysfunction of diabetes. |
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