| Aim:To induce Wistar rat model of diabetes induced cognitive deficits successfully?Methods:twelve male Wistar rats,weighting 300±10g,purchased from shanghai laboratory animal center,were housed in animal room in Nanjing medical laboratory animal center with 12 hour light dark cycle,humidity 65%±5%,and temperature 25±10??All rats were given food and water ad libitum?After one week acclimation,rats were randomly divided into two groups:Streptozocin group(STZ,n=6)and control group(CON,n=6)and were injected intraperitoneally streptozotocin(65mg/kg)and physiological saline(0.1mL/100g)respectively?Fourty-eight hours later,fasting blood glucose level was determined by enzymatic glucose oxidase peroxidase diagnostic kit,and blood glucose level>250mg/dl was regarded as diabetes?Five days after drug injection,body weight,fasting blood glucose level and cognitive function of all rats were evaluated?All rats received the non-visible platform trial twice per day(every morning and afternoon)for the first 5 days,a probe trial on the 6th day,and a visible platform trial on the 7th day.Each time,all rats were put into the pool from different quadrants(SE and NW)for training for 120 seconds and the plaeform was located in the center of WS quadrant.During the non-visible platform trial the escape latency(day 1-4)and swimming distance(day 5)to find the platform were recorded.If the mouse did not find the platform within 120 seconds,the escape latency was recorded as 120 seconds and then the rats were replaced on the platform for 20 seconds,the next training was performed after 120 seconds of rest.On day 6 of training,the platform was removed,and the number of crossings of the previous platform location(crossing number)and the percentage of time spent in target quadrant within 120 seconds was recorded?Results:1,All rats were successfully induced diabetes via intraperitoneally injection of streptozotocin(65mg/kg)and the level of fasting blood glucose were above 250mg/dl during the experiment process?2,According to the results of water maze test,mean escape latency and mean path length within 120s in streptozocin group rats were significantly higher than that of contrl group and the level of percentage of time spent in target quadrant and crossing numbers in streptozocin group rats was significantly lower than that of control group,indicating that the cognitive function of diabetes rats was impaired?Conclusion:Diabetes model of Wistar rats induced by intraperitoneally injection of streptozotocin(65mg/kg)is successful and the cognitive function of diabetes Wistar rats were significantly impaired?Objective:to evaluate the effect of astaxanthin on the DICD wistar rats and probe the underlying mechanisms?Methods:All Wistar rats(weighted 300±10g)were divided into three groups:control group,diabetes group,diabetes plus astaxanthin group which were then divided into three subgroups:diabetes plus astaxanthin 10mg/kg group(DM+AST(10)),diabetes plus astaxanthin 20mg/kg group(DM+AST(20))and diabetes plus astaxanthin 40mg/kg group(DM+AST(40))Diabetes induced cognitive deficits rats model were produced via injection of streptozotocin(65mg/kg)intraperitoneally,three astaxanthin subgroups were administered orally astaxanthin 10mg/kg,20mg/kg,40mg/kg per day five days respectively?The rats in control group were administrated equal amount of saline lavagely as placebo?After the treatment of drugs for five days,Morris water maze was introduced to evaluate the cognitive status of rats in each group?At the same time the oxidative stress of cerebral cortex and hippocampus,determined by the level of SOD,MDA and GSH and the level of inflammation moleculars in the same location determined by NF-?B p65,TNF-?,IL-? and IL-6 were investigated by ELISA.The activity of eNOS and iNOS of cerebral cortex and hippocampus were evaluated via radioimmunoassay.Real time PCR was used to determine the RNA level of caspase 3 and caspase 9,meanwhile the protein level of PI3K and p-AKT was determined by western blot in cerebral cortex and hippocampus respectively?Results:Compared with the Con group,the cognitive function was significantly impaired in DM group?The level of some related inflammatory markers(NF-?B p65,TNF-?,IL-1? and IL-6),activities of NOS(eNOS and iNOS)and mRNA level of caspase 3 and caspase 9 regarded as the regulator of cell apoptosis in DM group were significantly elevated in the cortex and hippocampus when compared with Con group(p<0.05 respectively)?But the protein levels of PI3K and p-AKT were not significantly reduced in DM group when compared with that in Con group?Compared with the DM group,the cognitive dysfunction was significantly improved in three astaxanthin subgroups?The levels of some related inflammatory markers(NF-kB p65,TNF-?,IL-1? and IL-6),activities of NOS(eNOS and iNOS)and mRNA level of caspase 3 and caspase 9 regarded as the regulator of cell apoptosis in each astaxanthin group were significantly inhibited in the cortex and hippocampus respectively when compared with DM group?Meanwhile the protein level of PI3K and AKT were significantly elevated in each astaxanthin group when compared with that in DM group.Conclusion:Astaxanthin has the potential protective function on diabetes induced cognitive deficit(DICD)through suppression of the oxidative stress,inflammatory reaction,activity of NOS,neuronal apoptosis and through upregulation of the PI3K/AKT pathway?... |
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