| Objective:With the rapid increase of the incidence of diabetes,the impairment of learning and memory ability caused by diabetes is also attracting widespread attention.The purpose of this study was to explore the effects of Coptis-Dried ginger on glucose and lipid metabolism,learning and memory ability and polarization phenotype of microglia in the brain of diabetic mice,and to further study the mechanism of Coptis-Dried ginger.Methods:Coptis was extracted by water,50%ethanol and 70%ethanol respectively,and the content of berberine in three kinds of Coptis extracts was determined by HPLC.A total of 170 SPF healthy male ICR mice were randomly divided into control group（n=20）and model group（n=150）.The model group was fed with high fat and high sugar diet for 4w,then intraperitoneally injected with STZ 80mg·kg-1 to replicate the diabetic model.After 7 days of model replication,fasting blood glucose level ≥11.1mmol·L-1 was considered as successful model replication.The mice were randomly divided into 5 groups:model group（n=20）,Coptis-Dried ginger-water extraction group（n=20）,Coptis-Dried ginger-50%ethanol extraction group（n=20）,Coptis-Dried ginger-70%ethanol extraction group（n=20）and sitagliptin group（n=20）.Each group of Coptis-Dried ginger was given 1.306g·kg-1 intragastric administration.Sitagliptin group was given 0.016g·kg-1 intragastric administration,once a day,for consecutive 8w.Body weight and fasting blood glucose levels were measured at 2,4,6 and 8w after administration,respectively,and autonomous activity experiment was conducted.New object recognition experiment was performed at 4 and 8w after administration.Morris water maze experiment and heat stimulation Y maze experiment were performed successively at 8w after administration.After behavioral experiments,OGTT and ITT experiments were performed to determine the glucose and lipid metabolism indexes of serum GSP,INS,Cpeptide,TC,TG,LDL-C and HDL-C of diabetic mice,and calculate HOMA-IR.The markers of M1-type microglia in brain tissues of each group were determined by ELISA:IL-6,IL-1βand TNF-α.M2 microglia markers:IL-4 and IL-10.The polarization changes of microglia in the brain of diabetic mice were described,and the regulatory effect of drug intervention on microglia polarization phenotype was reflected.In addition,morphological and structural changes of hippocampal and cerebral cortex neurons were observed by HE staining.Results:The content of berberine in the ethanol extract of rhizoma Coptis increased significantly compared with that in the water extract（P<0.01）,and there was no significant difference in the content of berberine between 50%and 70%ethanol extract.Compared with control group,blood glucose in model group was significantly increased（P<0.01,P<0.05）;Compared with model group,blood glucose in each drug group was significantly decreased successively（P<0.01,P<0.05）.OGTT showed that compared with control group,OGTTAUC and ITTAUC in model group were significantly increased（P<0.01）.Compared with model group,OGTTAUC and ITTAUC in all drug groups were significantly decreased（P<0.01,P<0.05）.Compared with control group,GSP,C-peptide,INS,HOMA-IR,TC and TG in model group were significantly increased（P<0.01）,while HDL-C was significantly decreased（P<0.01）.Compared with model group,GSP,INS,HOMA-IR and TC in all drug groups were significantly decreased（P<0.01,P<0.05）,HDL-C was significantly increased（P<0.01）,TG content in all drug groups was significantly decreased except Coptis-Dried ginger-water extraction group（P<0.01）.Behavioral experiment showed that compared with control group,activity number and standing number of mice in model group were significantly decreased（P<0.01）,relative recognition index of mice at 8w of administration was significantly decreased（P<0.01）,and escape latency of mice at 7th,8th and 10th times of Morris water maze navigation and test period was significantly increased（P<0.01,P<0.05）.The percentage of times of space exploration crossing the target quadrant was significantly decreased（P<0.01）,and the learning times and error times of thermal stimulation Y maze experiment were significantly increased（P<0.01）.Compared with model group,the activity number and standing number of all drug groups were significantly increased（P<0.01,P<0.05）except the activity number of Coptis-Dried ginger-water extraction group at the 4th week of administration,and the relative recognition index of sitagliptin group at the 8th week of administration was significantly increased（P<0.05）.The escape incubation period of the seventh positioning voyage and test period in Coptis-Dried ginger 70%ethanol extract group was significantly decreased（P<0.05）,the escape incubation period in sitagliptin group was significantly decreased（P<0.05）,and the percentage of crossing target quadrant times in each drug group was significantly increased（P<0.01）.The learning times and error times of mice in all drug groups were significantly decreased（P<0.01）.Compared with control group,the contents of IL-1β,IL-6 and TNF-α in model group were significantly increased（P<0.01）,while the contents of IL-4 and IL-10 were significantly decreased（P<0.01,P<0.05）.Compared with model group,the contents of IL-1β,IL-6 and TNF-α in drug group were significantly decreased（P<0.01,P<0.05）,the content of IL-4 was significantly increased（P<0.01）,and the content of IL-10 in sitagliptin group was significantly increased（P<0.05）.Morphological observation showed that compared with control group,hippocampal and cortical neurons in model group showed darker staining,less number,scattered arrangement,and some nuclei showed pyknosis.Compared with model group,each administration group had different degree of improvement.Conclusion:Coptis-Dried ginger can improve glycolipid metabolism in diabetic mice,and may improve neuronal injury by affecting the polarization phenotype of brain microglia,thereby enhancing their learning and memory ability... |
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