利拉鲁肽对糖尿病大鼠海马神经元的保护作用及可能机制

Neuroprotective effect and mechanism of liraglutide on hippocampal neurons in diabetic rats

目的探讨利拉鲁肽对糖尿病大鼠海马神经元的保护作用及可能机制。 方法选取随机血糖≥11.1 mmol/L的13周龄SPF级健康雄性GK大鼠24只作为实验组，将其随机分为糖尿病组（n＝12）和利拉鲁肽组（n＝12）。另选取与GK大鼠同周龄等体重的SPF级健康雄性Wistar大鼠10只作为正常对照组。适应性喂养2周后利拉鲁肽组给予利拉鲁肽（400 μg·kg－1·d－1）皮下注射，对照组和糖尿病组给予等量生理盐水皮下注射，持续给药8周。10周后记录大鼠的一般资料及生化指标。Morris水迷宫实验检测利拉鲁肽对糖尿病大鼠空间学习记忆的影响。HE染色观察海马神经元的形态。Western印迹法检测海马组织磷酸化（p）-IκB激酶（IκB kinase, IKK）β、p-NF-κB、NF-κB、Klotho、PRX2蛋白的表达。 结果Morris水迷宫实验显示利拉鲁肽可改善糖尿病大鼠的空间学习记忆能力。HE染色显示利拉鲁肽可明显减轻糖尿病大鼠海马神经元病理学损伤。Western印迹显示利拉鲁肽可抑制糖尿病大鼠海马组织NF-κB信号通路。糖尿病组海马组织Klotho蛋白表达显著低于对照组，PRX2蛋白表达高于对照组（t＝8.298、－7.398，均P〈0.01），利拉鲁肽组海马组织Klotho、PRX2蛋白表达高于糖尿病组（t＝－13.059、14.113，均P〈0.01），利拉鲁肽组海马组织Klotho蛋白表达与对照组相近（t＝－1.137，P〉0.05），PRX2蛋白表达显著高于对照组（t＝－28.055，P〈0.01）。 结论利拉鲁肽可能通过抑制糖尿病大鼠海马组织NF-κB信号通路，进而参与上调抗氧化蛋白Klotho、PRX2表达，减轻氧化应激，改善糖尿病大鼠海马神经元损伤，发挥神经保护作用，预防与延缓糖尿病脑病的发生。

ObjectiveTo investigate the neuroprotective effect and mechanism of liraglutide on diabetic rats. Methods24 healthy male SPF Goto-Kakizaki （GK） rats with random blood glucose greater than 11.1 mmol/L were selected as the experimental group, and randomly divided into diabetes mellitus group （n=12） and liraglutide group （n=12）. Ten healthy male SPF Wistar rats with the same age and weight as GK rats were selected as normal control group. After adaptively feeded for 2 weeks, the liraglutide group was given liraglutide （400 μg·kg-1·d-1, subcutaneous injection）, while the control group and diabetes mellitus group were given the same volume of saline, and continued to be administered for 8 weeks. After 10 weeks, data and biochemical indicators were recorded. Effects of liraglutide on learning and memory in diabetes mellitus rats were detected by Morris water maze test. HE staining observed the hippocampal neurons morphology. Western blotting method detected the expression of p- IκB kinase （IKK）β, p-NF-κB, NF-κB, Klotho, and PRX2 in hippocampus. ResultsMorris water maze test showed that liraglutide can improve the spatial learning and memory ability of diabetes mellitus rats. HE staining showed that liraglutide significantly reduced the pathological damage of hippocampal neurons of diabetes mellitus rats. Western blotting showed that liraglutide inhibited NF-κB signaling pathway in hippocampus of diabetes mellitus rats. The expression of Klotho protein in hippocampus of diabetes mellitus group was significantly lower than that of control group, while the expression of PRX2 protein was higher than control group （t=8.298, -7.398, all P〈0.01）. The expression of Klotho and PRX2 protein in hippocampus of liraglutide group were higher than diabetes mellitus group （t=-13.059, 14.113, all P〈0.01）. The expression of Klotho protein of liraglutide group was similar to that of control group （t=-1.137, P〉0.05）. The expression of PRX2 protein was significantly higher than control group （t=-28.055, P〈0.01）. ConclusionsLiraglutide may enhance the expression of antioxidant stress protein including Klotho and PRX2, by inhibiting NF-κB signaling pathway in hippocampus of diabetes mellitus rats, reduced oxidative stress and improved the injury of hippocampal neuronal in diabetes mellitus rats, which seems to play a neuroprotective effect, to prevent and delay the occurrence of diabetic encephalopathy.