磷酸西格列汀对糖尿病大鼠脑缺血再灌注损伤的保护作用

Sitagliptin phosphate protects diabetic rats against cerebral ischemia-reperfusion injury

目的 探讨磷酸西格列汀通过微小RNA-34a(miR-34a)调控沉默信息调节因子1(SIRT1)/插头蛋白1(FOXO1)通路对糖尿病大鼠脑缺血再灌注损伤的神经保护作用。方法 选取SPF级雄性SD大鼠40只,高脂喂养4周后腹腔注射链脲佐菌素30 mg/kg制备糖尿病模型,将造模成功大鼠采用随机数字表法分为假手术组、模型组、西格列汀组、胰岛素组,每组10只,对模型组、西格列汀组和胰岛素组采用Zea-Longa大脑中动脉线栓法建立脑缺血再灌注模型。缺血2 h再灌注24 h后采用Zea-Longa评分评价大鼠神经功能,采用MTT法检测脑梗死体积,苏木精-伊红染色观察各组大鼠脑组织梗死灶神经元变化情况,检测血清超氧化物歧化酶(SOD)、丙二醛,荧光定量PCR测定脑组织miR-34a表达,Western blot法检测脑组织SIRT1、乙酰化FOXO1、Bax、B淋巴细胞瘤2基因(Bcl-2)表达。结果 与假手术组比较,模型组神经功能评分、脑梗死体积、丙二醛、miR-34a、乙酰化FOXO1、Bax表达明显升高,SOD、SIRT1、Bcl-2表达明显降低,有统计学差异(P<0.05,P<0.01);与模型组比较,西格列汀组和胰岛素组神经功能评分、脑梗死体积、丙二醛、miR-34a、乙酰化FOXO1、Bax表达明显降低,SOD、SIRT1、Bcl-2表达明显升高,有统计学差异(P<0.05,P<0.01);与西格列汀组比较,胰岛素组神经功能评分、脑梗死体积、丙二醛、miR-34a、乙酰化FOXO1、Bax表达明显升高,SOD、SIRT1、Bcl-2表达明显降低[(47.67±1.08)U/ml vs(67.75±3.08)U/ml,P<0.05;0.80±0.01 vs 0.93±0.02,P<0.01;0.91±0.04 vs 1.45±0.07,P<0.01]。结论 磷酸西格列汀通过miR-34a调控SIRT1/FOXO1通路对脑缺血再灌注损伤具有神经元保护作用。

Objective To investigate the neuroprotective effect of sitagliptin phosphate on cerebral ischemia-reperfusion injury in diabetic rats by regulating silent information regulator 1(SIRT1)/plug protein 1(FOXO1) pathway via microRNA-34 a(miR-34 a).Methods Forty SPF male SD rats were subjected.After 4 weeks of high-fat feeding, intraperitoneal injection of 30 mg/kg streptozotocin was used to establish a diabetic model.Then the successful model rats were randomly divided into sham operation group, model group, sitagliptin group, and insulin group, with 10 mice in each group.Zea-Longa middle cerebral artery suturing was used to establish cerebral ischemia-reperfusion model for model group, sitagliptin group and insulin group.After 2 h of ischemia and 24 h of reperfusion, Zea-Longa score was used to evaluate the neurological function of rats, MTT staining to detect the volume of cerebral infarction, hematoxylin-eosin staining to observe the changes of neurons in the infarcted areas of the brain tissue, and reagent kits to determine the serum contents of superoxide dismutase(SOD) and malondialdehyde.The expression of miR-34 a in brain tissue was detected by real-time quantitative PCR,and the expression of SIRT1,acetylated FOXO1,Bax, and B-lymphoma 2 gene(Bcl-2) in the brain tissue was detected by Western blotting.Results Compared with the sham operation group, the neurological function score, cerebral infarction volume, malondialdehyde, and miR-34 a, acetylated FOXO1 and Bax levels were significantly increased, while SOD activity, and SIRT1 and Bcl-2 expression levels were obviously decreased in the model group(P<0.05,P<0.01).Compared with the model group, opposite differences in the above values were observed in the sitagliptin group and the insulin group(P<0.05,P<0.01).Compared with the sitagliptin group, the insulin group had notably elevated neurological function score, larger cerebral infarction volume, and higher malondialdehyde content and expression levels of miR-34 a, acetylated FOXO1 and Bax, and decreased SOD activity and SIRT1 and Bcl-2 levels(47.67±1.08 U/ml vs 67.75±3.08 U/ml, P<0.05;0.80±0.01 vs 0.93±0.02,P<0.01;0.91±0.04 vs 1.45±0.07,P<0.01).Conclusion Sitagliptin phosphate exerts neuronal protective effect on cerebral ischemia-reperfusion injury by regulating SIRT1/FOXO1 pathway through miR-34 a.