| Objective:To investigate the expression of liver X receptorα(LXRα) of the hippocampal neurons of the Streptozotocin (STZ)-induced type 2 diabetic rats.Method:1 40 male adult Wistar rats were randomly divided into three groups: normal control group (NC group), fatty control group (FAT group) and Diabetes Mellitus group (DM group). NC group was fed with normality diet, while FAT group and DM group were fed with a diet rich in fat and carbohydrate.2 After feeding 12 weeks, DM group was administered STZ by intra- peritoneal injections to induce diabetes, that the dose was 25 to 35 mg per kg body weight in 2-3 divided doses; while FAT group was administered of Citrate Buffer in the same dose.3 We monitored the fasting blood glucose (FBG) of all the rats after feeding 4, 8, 12, 16 and 20 weeks, and observed the abnormal appearance of the rats administrated with STZ.4 When the DM group developed diabetes for about 3 months, we detected the FBG, serum triglycerides (TG), total cholesterol (TC) and the concentration of fasting serum insulin (FINS), and calculated the insulin sensitivity index (ISI).5 We dyed the hippocampal tissue slices with toluidin blue, and compared the mean area of neurons among the three groups.6 To investigate the expression of the LXRαmRNA, we extracted the total RNA of the hippocampus and proceeded to reverse transcription-polymerase chain reaction (RT-PCR).7 We discerned the location and quantitation of the LXRαprotein in the hippocampus by immunohistochemisty, and made comparison among the groups. Result:1 The difference of symptoms:①The rats of DM group appeared some overt symptoms, such as polydipsia, polyphagia and polyuria after administration of STZ, accompanied with markedly decreased body weight (P<0.01).②Moreover, their response to stimulus were tardier than the rats of FAT group and NC group (P<0.01).2 The results of serum tests:①The data of FBG shows that there was no difference of statistical significance among the three groups before injection of STZ, while the FBG of DM group was significantly higher than the other two groups after administration of STZ (P<0.01).②The TG of DM group increased significantly (P<0.01), while there were no difference between FAT group and NC group (P>0.05). The mean value of TC show no difference among the three groups (P>0.05).③The FINS and ISI'were significantly increased in DM group and FAT group (P<0.01), furthermore, the ISI'of DM group was higher (P<0.01) than FAT while the FINS was same (P>0.05).3 The pathology of hippocampal neurons:①The mean area of hippocampal neurons showed no difference (P>0.05).②Besides, We failed to discover any pathological change signifying apoptosis.4 The expression of LXRαmRNA and protein in hippocampus:①By RT-PCR, we found that the expression of LXRαmRNA hadn't altered among the three groups (P>0.05).②By the method of immunohistochemistry, we could identify the LXRαprotein dyed brown in the nucleus and cytoplasm of the hippocampal neurons, but the data of quantitation showed no difference of statistical significance among DM group, FAT group and NC group (P>0.05).Conclusion:The Expression of LXRαmRNA and protein of the hippocampal neurons of the STZ-induced diabetic rats, which have suffered from type 2 diabetes mellitus for about 3 months, is not altered significantly. |
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