APP17肽对糖尿病小鼠学习记忆功能和海马NT-3、胆碱乙酰化酶神经元的影响

The effect of APP17 peptide on the function of learning and memory and NT-3、choline acetyltransferase neuron of hippocampus in diabetic mice

目的 观察糖尿病小鼠学习记忆功能及脑海马内神经营养因子ＮＴ－３、胆碱乙酰化酶神经元表达的变化，并观察ＡＰＰ１７ 肽（ＡＰＰ３１９～３３５）对上述指标的影响。 方法 用链脲佐菌素（Ｓｔｒｅｐｔｏｚｏｔｏｃｉｎ，ＳＴＺ）诱发糖尿病小鼠模型，并皮下注射ＡＰＰ１７ 肽，４ 周后行水迷宫试验；其后对小鼠进行灌注固定，取小鼠脑海马冰冻切片免疫组化染色。 结果 （１）糖尿病小鼠与给予ＡＰＰ１７ 肽的糖尿病小鼠的血糖差异无显著性，分别为（２９．２１±３．５２）、（２８．９１±３．２１）ｍ ｍ ｏｌ／Ｌ，但明显高于正常对照组（Ｐ＜ ０．０１）；（２）神经行为学检查：给予ＡＰＰ１７ 肽的糖尿病小鼠游完全程的时间及错误反应的次数均较未给予ＡＰＰ１７肽的糖尿病小鼠减少，而与正常对照组差异无显著性；（３）神经免疫组织化学实验：给予ＡＰＰ１７肽的糖尿病小鼠与对照组的ＮＴ－３ 阳性细胞数〔分别为（９０．４１±１５．４２）和（８８．７５±４．１６）个〕及染色灰度〔分别为（５６．２５±４．９５）和（６０．９２±５．４７）〕差异无显著性，但与糖尿病小鼠〔分别为（６１．７１±１３．４１）个、（８９．４８±１３．４８）〕差异有显著性（Ｐ＜ ０．０１），给予?

Objective To observe the function of learning and memory and the immunohistochemical change of hippocampus in diabetic mice and the protective effects of APP17 peptide from diabetes. Methods Mouse diabetic model was produced with streptozotocin and APP17 peptide as a protective agent was injected subcutaneously into diabetic mice. Four weeks later, water maze test was performed. After water maze test, fixative was injected intravascularly into the mice , brain was removed for preparation of cryostat sections, and immunohistochemical stain was done with neurotrophin 3 (NT 3),choline acetyltransferase antibodies. Results (1)The blood glucose level in diabetic mice with injection of APP17 peptide 〔(28 91±3 21)mmol/L〕was not significantly different from that in diabetic mice without injection 〔(29 21±3 52)mmol/L〕, but significantly higher than that in the control mice〔(9 41±0 74)mmol/L〕( P <0 01).(2)The water maze testing: the time for completion of whole swimming journey and the number of error reactions in diabetic mice with injection of APP17 peptide was not significantly different from those in the control mice, but significantly different from that in diabetic mice without injection. (3)Immunohistochemical change in hippocampus: the number of positive staining neuron and staining greyscale of NT 3 in diabetic mice with injection of APP17 peptide 〔(90 41±15 42)and (56 25±4 95)separately〕 was not significanly different from those in the control mice 〔(88 75±4 16) and (60 92±5 47)separately〕,but significantly different from those in diabetic mice without injection〔(61 71±13 41) and (89 48±13 48)separately〕( P <0 01).The number of positive staining neuron and staining greyscale of choline acetyltransferase in diabetic mice with injection of APP17 peptide 〔(10 31±3 71) and (82 40±17 74)separately〕was not significantly different from those in control mice 〔(12 24±3 28) and (79 40±15 34)separately〕, but significantly different from those in diabetic mice without injection〔(5 24±0 87) and (106 38±10 76)separately〕( P <0 05). Conclusion APP17 peptide improves the function of learning and memory of diabetic mice probably by means of NT 3 neuron secretion.