Effect And Mechanism Of Shengmai San On Learning And Memory Impairment Induced By Complex Of High Sugar And High Fat

Diabetic encephalopathy(DE),also known as diabetic cognitive impairment,was one of the serious complications of diabetes.The incidence rate was as high as 40%.It is a cognitive impairment caused by diabetes or changes in brain neurophysiology and structure.It was mainly manifested as memory loss.,Unresponsiveness and decreased concentration.Long-term persistent hyperlipidemia and hyperglycemia could cause learning and memory loss,seriously affect the quality of life and economic burden of patients with diabetes,and further exacerbate the risk of neurodegenerative diseases in the later period.It was of great significance to study the occurrence and development process and mechanism of diabetic cognitive dysfunction,and to find effective drugs for preventing and treating diabetes-induced learning and memory loss,to alleviate the suffering of diabetic patients and improve the quality of life of diabetic patients.Therefore,based on the establishment of a high-glucose and high-fat compound model to reduce learning and memory function,this paper studies the effect and related mechanism of traditional Shengmai powder on improving high-glucose and high-fat compound rat model to induce learning and memory loss.Provides effective drug candidates for learning and memory impairment.At the same time,we systematically study the effect and mechanism of learning and memory loss caused by single factor hyperglycemia and hyperlipidemia,and provide theoretical basis and research basis for studying the mechanism of learning and memory loss caused by diabetic encephalopathy.The main research results are as follows:1.Study on the effect and mechanism of Shengmaisan on improving high-sugar and high-fat learning and memory impairment1.1 Establishment of animal models of learning and memory impairment induced by high glucose and high fatThe use of high-fat feed combined with intraperitoneal injection of STZ(45 mg/kg)has a high success rate,low mortality,blood glucose(13.2±0.63 moL/L),reduced insulin secretion(7.28±2.25 moL/L),and blood lipid levels(TG:3.11±0.32 mmol/L;CHO:2.32 ±1.2 mmol/L)were abnormal.At the same time,the food intake and water intake of animals increased significantly,showing the typical "three more and one less phenomenon".Six weeks after the establishment of the model,blood glucose(14.4±0.97 moL/L),blood lipids(LDL:13.04 ± 0.34 mmol/L;HDL:1.18 ± 0.47 mmol/L;TG:1.08 ± 0.7 mmol/L;CHO:32.36 ± 6.8 mmol/L)with time-dependent increase and insulin level with time-dependent decrease(7.28 4.98moL/L),the results of the study show that high-fat diet combined with intraperitoneal injection of STZ(45mg/kg)can establish a clinically similar 3.Stable high-sugar and high-fat compound animal model.1.2 Shengmai san improves the learning and memory of Morris water maze in high-sugar and high-fat compound model ratsThe high-sugar and high-fat compound model was established by intraperitoneal injection of STZ and high-fat diet feeding in the rats established in the previous period.The learning and memory impairments of the model rats at 6 weeks mainly manifested in spatial reference memory and working memory impairment.Three weeks after modeling,the animals were randomly divided into groups according to blood glucose and body weight indexes,and the low,medium and high doses of Shengmai San(0.5,1.5,4.5g/kg)were given by intragastric administration.After 3 weeks of continuous administration,Shengmai Sansan could improve the spatial reference memory and working memory damage caused by the combination of high glucose and high fat.The improvement of spatial reference memory damage is mainly manifested in:the low dose of Shengmai Powder could significantly reduce the incubation period of positioning navigation D1-4 days,medium The rats in the high-dose group can significantly reduce the incubation period of the positioning navigation D1-3 roof;the low,medium and high doses of Shengmai San could significantly increase the number of space exploration rats crossing the platform,increase the stay time of the target quadrant,and affect the working memory.The main performance was that it can significantly reduce the platform seeking latency of the working memory stage model rats.At the same time,the low dose of Shengmaisan could significantly increase the activity time and average speed of rats in the empty field.The low and medium dose of Shengmaisan(0.5g,1.5g/kg)could significantly increase the activity time and average of the rats in the empty field.speed.1.3 Shengmaisan improves the object cognition of high-sugar and high-fat compound model ratsThe high-glucose and high-fat compound rat model showed object recognition non-spatial memory impairment at 6 weeks.New object position recognition experiments found that low,medium and high doses of Shengmai San could significantly increase the relative discrimination index of model rats.It suggests that it has a significant improvement effect on object recognition non-spatial memory impairment.1.4 Shengmaisan improves the high-sugar and high-fat compound model-induced learning and memory loss mechanismThe mechanism of Shengmaisan’s improvement of diabetes-induced learning and memory impairment is related to inflammation in the brain and regulation of neural plasticity PI3K-pAKT/AKT-pCREB/CREB-BDNF pathway protein.The pathological manifestations of hippocampus in high-sugar and high-fat model rats were neuroinfiltration,interstitial edema,hippocampal pyramidal cell necrosis and loose arrangement,Shengmaisan could significantly improve hippocampal tissue pyramidal cell necrosis and arrangement disorder and other pathological changes.The content of TNF-α and IL-1β in hippocampus of model rats with high glucose and high fat was significantly increased,while Shengmaisan could significantly reduce the content of TNF-α and IL-1β in hippocampus.It is suggested that Shengmai Powder can improve the inflammation in the brain.Western blot results showed that the protein expressions of SYN,BDNF,PI3K,pAKT/AKT,pCREB/CREB in hippocampus tissues of high-sugar and high-fat model rats were significantly reduced,and Shengmaisan could significantly increase the hippocampal tissues SYN,BDNF,PI3K,pAKT/AKT,PCREB/CREB protein expression.In addition,this study found that different doses of Shengmai Powder had no obvious effect on blood glucose and insulin in rats with high glucose and high fat models,but it could significantly reduce blood lipid TG and LDL levels,suggesting that Shengmai Powder improved learning and memory in high glucose and high fat model rats.The damage may be related to regulating body fat metabolism.2.Hyperglycemia and hyperlipidemia on learning and memory dysfunction and mechanism research2.1 The effect of hyperglycemia on learning and memory dysfunctionThe hyperglycemia model was established by intraperitoneal injection of STZ(45mg/kg).The single-factor hyperglycemia model rats had blood glucose values of 7.99±0.62,11.51±0.69,13.69±1.43mmol/L,insulin levels at 3 weeks,6 weeks,and 9 weeks,respectively.They were 8.04±0.31 mmol/L,Insulin:7.43±0.3 mmol/L,Insulin:5.21 ±0.67 mmol/L.The hyperglycemic model rats first appeared working memory impairment at 3 weeks,and working memory impairment,reference memory and non-spatial memory impairment occurred at 6-9 weeks.The main manifestation is that the memory impairment increases with time.High-glucose and high-fat model rats developed working memory impairment,reference memory and non-spatial memory impairment at 6 weeks.Among them,the blood glucose value was(14.4±0.97 moL/L,Insulin:4.98±0.49 moL/L),and the reduction rate of blood glucose and insulin levels(58.41%)in rats with high glucose and high fat for 6 weeks was significantly higher than that of single factor hyperglycemia 6 Week(24.7%),suggesting that blood glucose levels and insulin levels increase insulin resistance.The combination of high-sugar and high-fat may increase the intensity and duration of working memory impairment in single-factor hyperglycemic rats.The main manifestations were:compared with single-factor hyperglycemia,the incubation period of the 6-week working memory search platform for high-sugar and high-fat rats is(39.4±3.4 s),which was significantly higher than the 6-week working memory search platform latency of single-factor hyperglycemic rats(19.2±2.3 s),but there was no significant difference from the 9-week hyperglycemic working memory search platform latency of rats.6 weeks of high glucose and high fat did not aggravate the degree and time of non-spatial memory impairment of the water maze reference memory and new object recognition,mainly manifested in 6 weeks and 9 weeks of hyperglycemic and high fat model rats There is no significant difference between the memory and object recognition non-spatial memory damage degree discrimination index.Compared with the reference memory of the 6-week hyperglycemic water maze in rats,the high-glucose and high-fat compound model showed no significant difference in the number of reference memory crossing platforms and target quadrant time for 6-week and 9-week hyperglycemic rats.2.2 The effect of hyperlipidemia on learning and memory dysfunctionLong-term feeding of high-fat feed was used to establish a rat model of hyperlipidemia.The serum TG values of the model rats at 2 weeks,4 weeks,8 weeks,and 12 weeks were 1.92 ± 0.34,3.35±0.91,3.00 ± 0.24,3.87 ± 0.33 mmol/L;LDL values were 0.58 ± 0.13,0.70 ± 0.13,1.46 ± 0.51,1.73±0.31 mmol/L.The high-sugar and high-fat model showed blood lipids at 3 weeks(TG:3.11± 0.32 mmol/L;CHO:2.32± 1.2 mmol/L).Six weeks after the establishment of the model,blood glucose in high-sugar and high-fat rats(LDL:13.04± 0.34 mmol/L;HDL:1.18 ± 0.47 mmol/L;TG:1.08 ± 0.7 mmol/L;CHO:32.36± 6.8 mmol/L)Compared with the hyperlipidemia model,the high-glycemic-lipid model had no significant difference in TG levels between the 3-week rat and the 4-week rat.The hyperlipidemia model rats first had reference memory impairment at 4 weeks,working memory impairment at 8-12 weeks,and non-spatial memory impairment at 12 weeks.The main manifestation is that the hyperlipidemia rat’s positioning navigation latency is prolonged significantly at 4 weeks,and the number of space exploration crossing platforms is significantly reduced to 12 weeks,indicating that continuous hyperlipidemia has damage to learning and memory,especially reference memory is vulnerable to damage.The working memory results showed that the hyperlipidemia rats had a significantly prolonged incubation period of 8 weeks with memory impairment,which lasted up to 12 weeks;in the new object recognition test,the hyperlipidemia rats significantly reduced their ability to recognize new objects after 12 weeks.The 6-week reference memory impairment of the high-fat and high-glucose composite model may be related to the persistent state of high-fat,mainly manifested by the reference memory impairment at 4 weeks in high-fat rats,the reference memory impairment at 6 weeks in hyperglycemic rats,and the high-fat rats The time of memory impairment is earlier than that of hyperglycemic rats.With the 12-week high-fat rat new object recognition memory damage,the 6-week high-glucose and high-fat rat model showed damage,suggesting that the high-glucose and high-fat compound compounded the degree and time of non-empty memory impairment in high-fat rats.2.3 The mechanism of hypoglycemia and hyperlipidemia on learning and memory dysfunctionHypoglycemia-induced learning and memory dysfunction in rats is related to inflammation of hippocampus and PI3K-pAKT/AKT-pCREB/CREB-BDNF pathway.Mainly manifested in the model rats cerebrospinal fluid neurotransmitter dopamine levels decreased significantly at 9 weeks(6.24±2.16ng/mL).The levels of serum BDNF in hyperglycemic rats decreased at 6-9 weeks,the inflammatory factors TNF-α and IL-1β in hippocampus increased significantly,and the expression of pAKTAKT and pCREB/CREB protein in hippocampus decreased significantly.Hyperlipidemia-induced learning and memory impairment in rats is also related to hippocampal inflammation and BDNF-AKT-CREB pathway.Mainly manifested in the hyperlipidemia rats,hippocampal tissue inflammatory factor IL-1β content increased significantly in 4-12 weeks,BDNF content decreased significantly,in 8-12 weeks hippocampal tissue TNF-α increased significantly,hippocampal tissue CREB expression decreased.It is suggested that the mechanism of hypoglycemia and hyperlipidemia-induced learning and memory impairment is related to inflammation of hippocampus and CREB-BDNF pathway.To sum up,Shengmai Powder can significantly improve the learning and memory loss caused by the high-sugar and high-fat compound model,and can significantly improve the spatial reference memory and non-spatial memory damage and spatial working memory damage caused by the high-sugar and high-fat compound.San has a lipid-lowering effect and has no obvious effect on blood glucose and insulin levels.Its mechanism of action is related to the regulation of brain inflammation and neuroplasticity PI3K-pAKT/AKT-pCREB/CREB-BDNF pathway protein.Blood glucose level,insulin level and duration were highly correlated with the occurrence of learning and memory dysfunction.The duration and degree of high blood glucose level aggravate the impairment of reference memory and working memory in non-spatial memory by new objects in hyperglycemic rats,and first There is a working memory impairment.The duration and degree of high blood lipid levels aggravated the reference memory and working memory of high blood fat rats to identify non-spatial memory damage with new objects,and the reference memory damage first appeared.This study provides effective drug candidates for the development of new Chinese medicines for the prevention and treatment of diabetes associated with learning and memory impairment,and provides a research basis for studying the mechanism of learning and memory impairment caused by diabetic encephalopathy.