知母-黄柏药对有效部位群改善2型糖尿病大鼠认知功能障碍的药效及机制研究

Effects and mechanism of Anemarrhenae Rhizoma-Phellodendri Chinensis Cortex medicine effective parts to improve cognitive impairment in type 2 diabetic rats

目的研究知母-黄柏药对有效部位群通过磷脂酰肌醇-3激酶(PI3K)/蛋白激酶B(PKB/Akt)通路改善2型糖尿病模型大鼠认知功能障碍的药效及作用机制。方法 50只雄性SD大鼠随机分为5组,每组10只,分别为对照组、模型组、知母-黄柏药对有效部位群高剂量(ZBH,2.0 g/kg)和低剂量(ZBL,1.0 g/kg)组、盐酸美金刚(MHT,1.0 mg/kg)组;采用ip链脲佐菌素(STZ)联合喂食高脂饲料的方法制备2型糖尿病大鼠模型;造模成功后各组大鼠开始ig给药,连续给药20周,分别在给药8、16周时测定大鼠血浆中β淀粉样蛋白1-42(Aβ1-42)水平,并结合Barnes迷宫、Morris水迷宫法检测大鼠的认知能力;给药20周后,取大鼠胰腺、海马组织进行形态学观察;q RT-PCR检测PI3K、Akt、Bcl-2基因在大鼠脑组织中的表达。结果给药8、16周时,与对照组相比,模型组大鼠血浆中Aβ1-42蛋白水平显著升高(P<0.05、0.01),与模型组相比,MHT、ZBH组Aβ1-42蛋白水平均降低(P<0.05);行为学检测结果显示,与模型组相比,各给药组均能不同程度改善大鼠记忆能力(P<0.05、0.01);给药20周,大鼠海马CA1区病理结果显示,对照组大鼠海马区神经元排列整齐、形态规则、着色均匀。模型组大鼠大量神经元细胞核深染、固缩,神经元细胞排列紊乱,部分细胞被小胶质细胞代替。与模型组相比,ZBH、ZBL可有效改善大鼠海马组织神经元形态及细胞排列形态,修复神经损伤;q RT-PCR结果显示,与对照组相比,模型组大鼠脑组织PI3K、Akt mRNA表达有一定程度的降低,抗凋亡基因Bcl-2 mRNA表达减弱(P<0.05),MHT、ZBH均能不同程度上调PI3K、Akt、Bcl-2 mRNA的表达(P<0.05、0.01)。结论知母-黄柏药对有效部位群能明显降低Aβ1-42蛋白水平,上调PI3K、Akt mRNA的水平,对海马神经元具有修复和保护作用,说明知母-黄柏药对有效部位群可能通过调节PI3K/Akt通路而实现对2型糖尿病大鼠认知功能障碍的改善。

Objective To study the effects of Anemarrhenae Rhizoma-Phellodendri Chinensis Cortex medicine effective parts on phosphatidyl inositol 3 kinase（PI3 K）/protein kinase B（Akt） signaling pathway and explore its mechanism of action to improve brain cognitive of type 2 diabetes rats. Methods A total of 50 male SPF SD rats, divided into five groups with 10 for each group, named as control group, model group, high/low dosage of Anemarrhenae Rhizoma-Phellodendri Chinensis Cortex medicine effective parts（ZBH and ZBL） group, and Ebixa（MHT） treatment group; The rats were immunized with ip of streptozotocin（STZ） jointly fed high-fat diet for three weeks. Then the rats were continuously gavaged with ZBH, ZBL, and MHT for 20 weeks, the serum Aβ1-42 levels were determinated in 8 th and 16 th week respectively, the changes of the cognitive impairment were analyzed, combined with Barnes maze and Morris water maze to detects the cognitive ability of each group rats; At the end of 20 weeks of administration, dissecting and preservatting the rat pancreatic tissue, the hippocampus to made into routine pathological sections and brain tissue pathology morphology inspection and PI3 K, Akt, and Bcl-2 m RNA expression by fluorescence quantitative PCR method detection. Results After treatment for 8 weeks and 16 weeks, compared with control group, Aβ1-42 levels of model group were significantly increased（P〈0.05, 0.01）; Administration 20 weeks, compared with control group, pathological section results showed normal hippocampus cells arranged in neat rows, morphological rules, and color is very even. DM models of hippocampal tissue cells arranged scattered through the administration significantly after repair. Compared with model group, ZBH and ZBL could effectively improve the form of neurons and cell arrangement of rat＇s hippocampus, repairing nerve injury; Compared with control group, PI3 K and Akt m RNA expression of hippocampal tissue of model group rats decreased, Bcl-2 m RNA expression was abate（P〈0.05）. After delivery, MHT and ZBH group could significantly improve the level of PI3 K, Akt, and Bcl-2 m RNA expression（P〈0.05, 0.01）. Conclusion Anemarrhenae Rhizoma-Phellodendri Chinensis Cortex medicine effective parts can significantly reduce the accumulation of Aβ1-42 protein, and decreased the expression of PI3 K and Akt, indicating that the effects of improvement of cognitive impairment in type 2 diabetic rats may be achieved through regulation of PI3 K/Akt pathway.