| Objective: Cognitive disfunction in diabetes including the decrement ofthe ability on learning,memoring and computing caused by the abnormality ofblood glucose。The imbalance of oxidative stress and antioxidative stresscaused by diabetes was involved in the process and development of thedisease。NAD(P)H: Quinone Oxidoreductase1(NQO1)was a flavoprotein andprotective reductase, when the body was attacked by oxidative stress, theexpression of NQO1was increased,and then could enhance the antioxidantability of the body. The present study was designed to majorly observe thechanges of hippocampal NQO1of diabetic rats with cognitive disfunction andthe efficacy of the antioxidant herbal medicine-troxerutin on improvingdiabetic cognitive deficits。Methods:70male Sprague Dawley(SD)rats weighting150-170g wererandomly divided into two groups:normal control group(NC,n=10),diabeticcontrol group(DM,n=60)。The rats were fed by normal forage for one week,after fasting for12hours,the rats in DM were injected intrapertoneally asingle dose of1%Streptozotocin(60mg/kg),the animals in group NCreceived the equal volume of citrate buffer solution by intrapertonealinjection。After72hours,the blood sample were collected through tail veinand plasma glucose levels were estimated,the rats having plasma levels morethan16.7mmol/L were selected,then the blood glucose leves were estimatedevery week,if the rats having plasma levels less than16.7mmol/L wereexcluded。At1and12weeks,the rats in group NC and DM were received theMorris water maze test after the successful modeling。After the end of12weeks of water maze test, the rats in group DM were randomly divided intofour groups:diabetic control group(DC,n=15),diabetic group treated withnormal saline(DN,n=15), diabetic group treated with α-lipoic acid(DL,n=15),and diabetic group treated with troxerutin(DT,n=15)。Since13weeks, the rats in group DL were administered intrapertoneally α-lipoic acid(60mg.kg-1.day-1) and in group DT troxerutin (60mg.kg-1.day-1) was injectedintrapertoneally,the group DC and NC received the same volume of saline for6weeks。At18weeks,all animals accepted Morris water maze test and weresacrificed,the hippocampuses were took out。The Western-blot and Real-timepolymerase chain reaction(R-T PCR) were carried out to measured theexpression of NQO1protein and mRNA in the hippocampus,the activity ofsuperoxide dismutase(SOD)and the content of malonaldehyde(MDA) in thehippocampus were detected using the methods of xanthine oxidase andthiobarbituric acid。All the datas were dealed with statistical software packages SPSS13.0,the datas were analyzed using repeated measures and multivariate analysis ofvariance(ANOVA) process and Oneway ANOVA of completely randomdesign,the results were expressed as the mean±standard deviation。Statisticalsignificance was set at p＜0.05。Results:1. General considerationAfter the successful modeling,the rats in group DM appeared distinctsymptoms of polydipsia,polyphagia,polyuria and weight loss。With thedevelopment of the experiment,the blood glucoses of diabetic rats fluctuatedhigher levels(＞20.0mmol/L),meanwhile,the colour of diabetic rats turnedyellow, the skin became thinner, listlessness, irritability。 During theintervention,general condition of the rats was better in group DT than ingroup DL。The growth and nutritional state of rats in group NC was well,therewere no above diabetic symptoms。2. The changes of body weight and blood glucose levelsCompared to normal rats,the blood glucoses and body weights of the ratsin group DM had no statistical significance(p＞0.05)before modeling。Afterintervention(18w),the blood glucoses of rats in DC(28.29±2.79),DN(29.25±3.18),DT(27.77±2.66),DL(30.54±3.31) had an significant increasement as compared to the normal rats,but the weights over the sameperiod were found to be significantly decreased(p＜0.01)。When theintervention was finished,the blood glucoses and body weights of rats indiabetic subgroup(DC,DN,DT,DL) were no statistical significance(p＞0.05)。3. Results of Morris water testsResults of Morris water tests at1week showed: compared with the groupNC,the escape latency periods of the rats in group DM were no statisticalsignificance(p＞0.05),indicating that there was no difference in cognitivefunction between the two groups。Results of Morris water tests at12weeks(before intervention) showed:compared with the group NC,the escape latency periods of the rats in groupDM were significantly extended(p＜0.05),and the escape latency periods inthe two groups were statistical significance(p＜0.05)at the same time,thenit indicated the diabetic rats appeared cognitve deficits。Results of Morris water tests at18weeks(after intervention) showed: ascompared to group NC,the escape latency periods in group DC,DN,DT,DL were all increased(p＜0.05);and the escape latency periods in group DT,DL were decreased as compared to groupDC/DN. There was no statisticalsignificance(p＞0.05)between group DT and DL, DC and DN。4. Expression of NQO1mRNA in the hippocampusReal-time PCR showed：compared with the group NC(1.00±0.00),theexpression of hippocampal NQO1mRNA had significantly decreased(p＜0.01)in the rats of group DC(0.70±0.04)and DN(0.72±0.08)。As comparedto group DC/DN,the expression of hippocampal NQO1mRNA was found tobe significantly increased(p＜0.01)in the rats of both group DT(1.18±0.09)and DL(1.13±0.05)。There was no statistical significance(p＞0.05)betweengroup DT and DL,DN and DC。5. Expression of NQO1protein in the hippocampusWestern-blot showed: compared with the group NC(1.00±0.00), theexpression of hippocampal NQO1protein had significantly decreased(p＜ 0.01)in the rats of group DC(0.44±0.05)and DN(0.44±0.04)。As comparedto group DC/DN,the expression of hippocampal NQO1protein was found tobe significantly increased(p＜0.01) in the rats of both group DT(1.14±0.05)and DL(1.19±0.05)。There was no statistical significance(p＞0.05)betweengroup DT and DL,DN and DC。6. Measurement of hippocampal SOD activity and MDA concentrationCompared with the group NC(SOD:115.98±7.57MDA:2.74±0.21),thehippocampal SOD activity had significantly decreased(p＜0.01)in the rats ofgroup DC(SOD:61.81±3.94MDA:3.83±0.11) and DN(SOD:68.24±7.62MDA:3.71±0.20),the content of MDA was found to be significantly increased(p＜0.01),As compared to group DC/DN,the hippocampal SOD activityhad significantly decreased(p＜0.01)in the rats of both group DT(SOD:191.99±11.41MDA:2.53±0.201)and DL(SOD:200.32±6.17MDA:2.02±0.23),the hippocampal SOD activity was no statistical significance(p＞0.05)between group DT and DL,but there was more the content of MDAingroup DT than in group DL(p＜0.05)。the hippocampal SOD activity and thecontent of MDA were both no statistical significance(p＞0.05) between groupDN and DC。Conclusion:1. Diabetes mellitus could resulted in cognitive dysfunction,it would decreasethe level of NQO1and the activity of SOD both possessing antioxidativeability and increase the content of MDA produced by oxidative stress in thehippocampus。2. α-lipoic acid could ameliorate diabetic cognitive deficits,it can increase theexpression of NQO1and the activity of SOD and reduce the generation ofMDA in the hippocampus。3. Troxerutin possess the ability of antioxidative stress,compared to. α-lipoicacid, it can play similar efficacy on improving diabetic cognitivedysfunction,but its antioxidant effects may be weaker。... |
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