Effects Of PTP1B Inhibitor Claramine On Learning And Memory Impairment In Diabetic Mice

Objective: To investigate the preventive and therapeutic effects of PTP1 B inhibitor claramine on learning and memory impairment in diabetic mice.Methods: Fifty-four 8 weeks male C57BL/6J mice were divided into Con group,DM group,DM+CA group and CA group.DM group was induced by high-fat diet combined with streptozotocin(40 mg/kg).The drug group was given CA(10 ?g/12 ?L)intranasally for 6 weeks.The protein expression of PTP1 B in hippocampus was observed by immunohistochemistry.The relationship between PTP1 B and diabetes cognitive impairment was predicted by network pharmacology.The spatial learning and memory levels of mice in each group were evaluated by WMW.FBG?IPGTT and ITT were used to detect the blood glucose level of mice in each group.The levels of blood lipid metabolism of mice in each group were detected by TC,TG,HDL-C and LDL-C.The hippocampal injury of mice in each group was observed by H?E staining and Nissl staining;The ultrastructure of hippocampus and the expression of synaptic protein were observed by electron microscopy and western blot.The expression of NLRP3 inflammation signaling pathway and insulin signaling pathway related proteins in hippocampus of mice in each group were detected by western blot.The expression of PTP1 B in hippocampus of mice in each group was detected by western blot,real-time fluorescence quantitative PCR and immunofluorescence.Results:(1)Immunohistochemical results showed that the expression of PTP1 B protein in hippocampal CA1,CA3 and PFC regions in DM group was significantly higher as compared with those in Con group.(2)Network pharmacology analysis shows that PTP1 B is the core target of diabetic cognitive impairment.(3)MWM showed that escape latency had longer,and residence time in target quadrant and times of crossing the platform had shorter in the hippocampus of DM group as compared with those in Con group;escape latency had shorter,and residence time in target quadrant and times of crossing the platform had longer in the hippocampus of DM+CA group as compared with those in DM group.(4)The results of body weight and blood glucose showed that DM group lost weight and blood glucose increased compared with Con group;the weight and blood glucose of DM + CA group returned to normal compared with DM group.(5)The results of biochemical indexes showed that the levels of TC,TG and LDL-C in DM group increased significantly,and the level of HDL-C decreased significantly compared with Con group;the levels of TC,TG and LDL-C in DM + CA group decreased significantly,and the level of HDL-C increased significantly compared with DM group.(6)The results of H?E staining and Nissl staining showed that the hippocampal neurons in CA1,CA3 and DG areas in DM group were seriously damaged compared with Con group;the hippocampal neurons in DM+CA group was significantly reduced compared with DM group.(7)The results of electron microscopy showed that there were nuclear shrinkage,mitochondrial vacuolization and endoplasmic reticulum degranulation as compared with those in DM group;after CA administration,the above phenomenon was significantly reversed.(8)Western blot showed that the protein expression of PSD-95,SYN-1,SYP,p-IRS1,p-PI3 K,p-AKT and p-GSK-3? in hippocampus of DM group were significantly decreased,the protein expression of NLRP3,ASC,Caspase-1,COX-2,IL-1?,TNF-? and PTP1 B were significantly increased compared with Con group;the protein expression of PSD-95,SYN-1,SYP,p-IRS1,p-PI3 K,p-AKT and p-GSK-3? in hippocampus of DM+CA group were significantly increased,the protein expression of NLRP3,ASC,Caspase-1,COX-2,IL-1?,TNF-? and PTP1 B were significantly decreased compared with DM group.(9)The results of real-time fluorescence quantitative PCR showed that there was no significant difference in the m RNA expression of PTP1 B in each group of mice.(10)Immunofluorescence results showed that the protein expression of PTP1 B in CA1 and CA3 regions of hippocampus in DM group were significantly increased compared with Con group;the protein expression of PTP1 B in CA1 and CA3 regions of hippocampus in DM+CA group were significantly decreased compared with DM group.Conclusion:(1)the expression of PTP1 B protein in hippocampus CA1,CA3 and PFC increased in diabetes mice.(2)Network pharmacology predicts that PTP1 B is a key target for diabetic cognitive impairment.(3)Claramine can improve the spatial learning and memory impairment of diabetes mice.(4)Claramine can improve the ultrastructure of diabetes mice and alleviate the damage of hippocampal neurons;(5)Claramine can improve the learning and memory impairment of diabetes mice by decreasing the expression of PTP1 B,inhibiting the NLRP3 signaling pathway and regulating the insulin signaling pathway.