| Objectives To explore the effect of nuclear factor erythroid 2-related factor 2(Nrf2)on cognitive dysfunction in type 2 diabetes mellitus(T2DM)mice.To study the mechanism of berberine on cognitive dysfunction in type 2 diabetes mice,and whether berberine exerts neuroprotection through Nrf2 signaling pathway It can provide new ideas for the treatment of diabetic cognitive decline.Methods A selection of 25g～30g SPF 8-week-old male ICR wild type(WT)mice and Nrf2 knock-out(KO)mice were selected,60 in each group,and the mice were randomly divided into the following 8 groups : wild control group(WT-NC),wild diabetes group(WT-DM),wild control group(WT-NC+BBR),wild diabetes group(WT-DM+BBR),knock-out control group(KO-NC),knock-out diabetes group(KO-DM),knock-out control group(KO-NC+ BBR)and knock-out diabetes group(KO-DM+BBR),15 mice in each group.Mice in each diabetic group were fed with high fathigh sucrose diet(HFD),and the control group was fed with normal diet(ND).After 2 months,mice in DM group were injected intraperitoneally with 50 mg/kg streptozotocin(STZ),while the control group was given an intraperitoneal injection of the same amount of citrate buffer.The body weight and fasting blood glucose of each group of mice were recorded.Morris water maze experiment was used to evaluate the behavioral ability of mice;Nissl staining of hippocampus was used to observe the effect of berberine on hippocampal neurons of T2 DM mice;Western blotting was used to determine oxidative stress-related factors such as Nrf2 in hippocampus heme oxygenase-1(HO-1),NAD(P)H:quinone oxidoreductase(NQO1)and inflammatory factors such as tumor necrosis factor-α(TNF-α)and interleukin-1β(IL-1β)and nuclear factorκappa-B(NF-κB)protein expression;detect the effect of berberine on oxidative stress indicators(MDA)in the hippocampus of T2 DM mice;use q RT-PCR To detect the effect of berberine on the m RNA expression of Nrf2,HO-1 and NQO1 in the hippocampus of T2 DM mice.Results 1 Compared with the normal group,the weight of mice in the high-fat group increased significantly after feeding for 2 months(P<0.01).Compared with the WT-NC group,the body weight of the WT-DM group mice was significantly increased,while the body weight of the WT-DM+BBR group mice was reduced(P<0.05).Compared with the KO-NC group,the body weight of the mice in the KO-DM group was significantly increased(P<0.01),but there was no significant decrease after administration.2 Compared with the WT-NC group,the blood glucose of the mice in the WT-DM group was significantly increased(P<0.01).After the intervention of berberine,the blood glucose of mice in the WT-DM+BBR group decreased(P<0.05).In knockout group,compared with the WT-DM group,the blood glucose of the KO-DM group increased significantly,and after the intervention of berberine,the blood glucose decreased(P<0.05).3 The Morris water maze showed that there was no significant difference in swimming speed between the mice in each group;compared with the WT-NC group,the escape latency of the WT-DM group was prolonged,the stay time in the target quadrant was prolonged,after BBR treatment,the latency was shortened and the stay time in the target quadrant was prolonged(P<0.05);compared with WT-DM,the cognitive impairment of the KO-DM group mice was more severe,manifested by a significantly longer escape latency and shorter staying time in the target quadrant(P<0.05),there is no significant difference before and after administration.4 The results of Nissl staining showed that the hippocampal neuron cells of the WT-NC group were round,neatly arranged,and the nucleoli were obvious.The nerve cells of the WT-DM group were shrunken and deeply stained,some cells were degeneration,necrosis,and intercellular space.The neuronal cell morphology of mice in the WT-DM+BBR group was significantly improved after drug intervention.The neuronal cell atrophy and nuclear lysis in the KO-DM group were more severe than in the WT-DM group;The cell count under the microscope showed that the number of neurons in the WT-DM group was significantly reduced.After drug intervention,compared with the WT-DM group,the number of hippocampal neurons in the WT-DM+BBR group increased,while the KO-DM group was similar to WT-DM.The cell loss was more significant than that,and the differences were statistically significant(P<0.05).5 The test results of MDA content showed that compared with the WT-NC group,the hippocampal MDA content of the WT-DM group was significantly higher,while the MDA of the WT-DM+BBR group was lower;the MDA content of the KO-DM group was higher than KO-NC group(P<0.05).6 Western Blot detection of Nrf2 related protein expression results showed that compared with the WT-NC group,the Nrf2,HO-1,and NQO1 protein expression levels in the hippocampus of the WT-DM group were significantly decreased(P<0.05).After drug intervention,Compared with the WT-DM group,the expression levels of proteins in the WT-DM+BBR group increased(P<0.05),while there was no expression of Nrf2 protein in the hippocampus of the KO-DM group,and HO-1,NQO1 proteins Significantly reduced(P<0.05),and there was no significant change before and after administration.7 Western Blot detection of inflammatory factor protein expression results showed that the hippocampal NF-κB,TNF-α and IL-1β protein expression levels of the WT-DM group were significantly higher than those of the WT-NC group.After drug intervention,it was compared with the WT-DM group.In contrast,the expression levels of protein in the WT-DM+BBR group were reduced(P<0.05).8 The results of q RT-PCR showed that the expression level of Nrf2 m RNA in the hippocampus of the WT-DM group was significantly lower than that of the WT-NC group(P<0.05);there was no expression of Nrf2 m RNA in each KO group.Compared with the WT-NC group,the m RNA expression of each protein in the hippocampus of the WT-TDM group was significantly down-regulated(P<0.05),and the Nrf2,HO-1 and NQO1 m RNA protein expression levels in the WT-DM+BBR group increased(P<0.05);the expression of HO-1and NQO1 m RNA in the KO-NC group and the KO-DM group was significantly lower than that of the corresponding wild group,and there was no significant difference in the expression after medication intervention.Conclusions 1 Hyperglycemia induces oxidative stress and inflammation,damages the hippocampal neurons of mice,and further leads to cognitive dysfunction.2 Nrf2 gene is a protective gene for diabetes-related cognitive decline.Nrf2 gene knockout will aggravate the oxidative stress and inflammation in the hippocampus of type 2 diabetic mice,which will lead to more serious nerve cell damage and aggravate cognitive impairment.3Berberine can activate the Nrf2/HO-1 signaling pathway,inhibit oxidative stress and inflammation in the body,thereby effectively improving cognitive function.Figure19;Table1;Reference 124... |
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