Effects Of N-butylphthalide On Cognitive Function And Its Mechanisms In Db/db Mice

Background Diabetes is a chronic metabolic disease characterized by hyperglycemia.In clinical practice,correct and regular use of hypoglycemic drugs to control blood glucose can reduce the damage to various organs and systems caused by hyperglycemia,however,there is no good solution for cognitive impairment in the later stage of diabetes development.Current studies have shown that the mechanisms of cognitive impairment in diabetic patients include:abnormal glucose-insulin metabolism;Damage to synaptic plasticity,mitochondrial structure and function;Oxidative stress injury and apoptosis of hippocampal cells;Brain microvascular disease,etc.N-Butylphthalide(NBP),as a first-line drug for the treatment of acute cerebral infarction,has many pharmacological effects,such as rebuilding brain microcirculation,anti-oxidative stress,improving mitochondrial function,and reducing nerve cell death.Therefore,this study used db/db diabetic cognitive impairment model mice to explore the effects of different doses of butylphthalide injection on their cognitive function,in order to provide new ideas for the study of the pathogenesis of diabetic cognitive impairment and potential clinical treatment methods.Methods Twenty db/db mice were randomly divided into four groups:model group,low-dose,medium-dose and high-dose butylphthalide treatment group.There were 5 mice in each group and 5 normal db/m mice in the same litters as control group.At the age of 6 weeks,db/db mice in the low,medium and high dose butylphthalide treatment group were intraperitoneally injected with 20,40 and 60mg/kg,respectively,and the control group and model group were intraperitoneally injected with the same volume of normal saline,once a day,for consecutive 6 weeks.Body weight and fasting blood glucose levels were monitored every week.The open field test,new object recognition test and Morris water maze test were used to evaluate the cognitive ability of mice in each group.Western-blot and immunohistochemistry were used to detect the expression of Synaptophysin(SYN)and Postsynapticdensity 95(PSD-95)in the hippocampus of mice in each group.The number and structure of mitochondria and synapses in the hippocampus of each group were observed by electron microscopy.Serum oxidative stress indexes were detected by enzyme-linked immunosorbent assay(ELISA).The effects of different doses of butylphthalide on each organ were observed by pathological examination.In addition,the effects of different doses of butylphthalide on oxidative stress level and apoptosis of human umbilical vein endothelial cells(HUVECs)in high glucose environment were investigated.Results db/db mice showed cognitive impairment at 13 weeks of age compared with normal mice.The cognitive function of the NBP treatment group was improved compared with the model group.The relative expression of synaptophysin and postsynaptic density 95 protein in the hippocampus of the model group decreased,while the relative expression of synaptophysin and postsynaptic density 95 protein in the hippocampus of the treatment groups increased.In the model group,synapses were damaged,mitochondrial crest structure was sparse,fusion,membrane structure was damaged and vacuolated under electron microscope.The synaptic and mitochondrial ultrastructural damage were improved in the treatment group.Oxidative stress index showed that butylphthalide played a protective role in oxidative stress injury.In cell experiments,we found that NBP also exerts an anti-oxidative stress effect on endothelial HUVECs in high glucose environment and reduces cell apoptosis.Conclusion NBP can improve the cognitive function of db/db mice by increasing the expression of SYN and PSD-95 in hippocampus,improving the structure and function of synapses and mitochondria,and reducing the level of oxidative stress.