亚慢性铝暴露致大鼠认知障碍的Sirt1-Keap1/Nrf2信号通路机制

目的:观察亚慢性铝暴露对大鼠海马沉默信息调节因子1(silent information regulator 1,Sirt1)、Kelch样环氧氯丙烷相关蛋白(Kelch-like ECH-associated protein-1,Keap1)、核因子E2相关因子2(nuclear factor E2-related factor2,Nrf2)和微小RNA-128-3p(miR-128-3p)表达水平的影响,探讨miR-128-3p和Sirt1-Keap1/Nrf2信号通路在铝致大鼠认知障碍中的机制。方法:选取32只6周龄SPF级健康雄性SD大鼠,体重(190±20)g,按体质量随机分为4组:对照组、低剂量(10μmol/kg)组、中剂量(20μmol/kg)组和高剂量(40μmol/kg)组,每组8只。腹腔注射麦芽酚铝建立大鼠染毒模型。染毒结束后,Morris水迷宫实验来检验大鼠的学习记忆能力,Western blot检测大鼠海马组织中Sirt1、Keap1和Nrf2蛋白的表达,RT-qPCR检测海马组织miR-128-3p的表达,冰冻切片荧光染色检测大脑皮层活性氧(reactive oxygen species,ROS)水平。结果:(1)在定位巡航实验中,第3、4和5天铝暴露组大鼠的逃避潜伏期均显著高于对照组(P<0.05)。第6天,高剂量组与对照组和低剂量组相比穿越平台和平台象限的次数均减少(P<0.01)。(2)各组大鼠海马组织中Sirt1和Nrf2的相对表达水平随着麦芽酚铝暴露剂量的增加逐渐降低;Keap1的相对表达水平随着麦芽酚铝暴露剂量的增加逐渐升高,且高剂量组中miR-128-3p相对表达水平显著高于对照组(P<0.05)。(3)随着染毒剂量的增加,大鼠海马中谷胱甘肽过氧化物酶的含量逐渐减少,ROS水平逐渐升高。结论:亚慢性铝暴露可激活大鼠海马中miR-128-3p的表达,抑制Sirt1-Keap1/Nrf2通路,使Sirt1-Keap1/Nrf2通路不能被激活发挥抗氧化能力,大鼠的抗氧化系统失衡,导致大鼠神经细胞氧化损伤,表现为大鼠的认知功能降低。

Mechanism of hesperidin improving myocardial ischemia/reperfusion injury in type 2 diabetic rats through SIRT1/Nrf2/HO-1 signaling pathway

Objective:To observe the protective effect of hesperidin on myocardial ischemia/reperfusion injury in type 2 diabetes mellitus and its effect on SIRT1/Nrf2/HO-1 signaling pathway.Methods:50 Sprague-Dawley(SD)rats were randomly assigned to the normal control group(NC),model group,ischemia-reperfusion group(IR),hesperidin group,SIRT1 inhibitor group and hesperidin plus SIRT1 inhibitor group.In addition to NC,the rats in the remaining groups were replicated by intraperitoneal of high-fat diet combined with injection of streptozotocin for type 2 diabetic rats.After then,the myocardial ischemia/reperfusion injury(MIRI)rat model was established by LAd for 30 minutes with 2 hours reperfusion.He staining was used to observe the pathological changes of myocardial tissue,and the levels of serum LDH,CK-MB and SOD,GSH and MDA in myocardial tissue were detected by kit methods,and the expression abundance of related proteins in 4-HNE and SIRT1/Nrf2/HO-1 signal pathway were detected by immunohistochemistry and Western blot;Results:Hesperidin could significantly inhibit cardiomyocyte necrosis and inflammatory cell infiltration,reduce LDH activity,CK-MB and MDA level,and increase SOD activity,GSH and 4-HNE level,the differences were statistically significant when compared with IR group(P<0.01).In addition,compared with the ischemia-reperfusion group,the expressions of SIRT1,Nrf2 and HO-1 proteins in hesperidin group were significantly up-regulated,the differences were statistically significant(P<0.01);Conclusion:Hesperidin inhibits oxidative stress by activating SIRT1/Nrf2/HO-1 signaling pathway,and play a protective effect of myocardial ischemia reperfusion injury in diabetic rats.

盐酸纳美芬缺血后处理通过Sirt1/Nrf2/HO-1轴抑制铁死亡途径减轻大鼠肺缺血-再灌注损伤

目的研究纳美芬缺血后处理通过激活Sirt1/Nrf2/HO-1轴抑制铁死亡途径减轻肺缺血-再灌注损伤的作用及其机制。方法将60只大鼠随机均分为假手术组、模型组(I/R)、纳美芬组、纳美芬+EX527组、纳美芬+ML385组、纳美芬+Fe-柠檬酸盐组共6组,每组10只。假手术组大鼠不行缺血再灌注处理,未予药物治疗。I/R组大鼠采用阻断左肺门法建立肺缺血-再灌注模型,未给予药物治疗。纳美芬组大鼠于肺循环再灌注前5 min予尾静脉注射纳美芬(15μg/kg)。纳美芬+EX527组、纳美芬+ML385组、纳美芬+Fe-柠檬酸盐组分别于造模前2 h腹腔注射EX527(5 mg/kg)、ML385(30 mg/kg)、Fe-柠檬酸盐(15 mg/kg),同时在肺循环再灌注前5 min时尾静脉注射纳美芬(15μg/kg)。各组大鼠于再灌注3 h末留取处死后留取左肺上叶组织,检测肺组织湿/干重比值,评估各组大鼠肺组织损伤程度,检测肺组织Fe^(2+)、MDA和TNF-α、IL-6含量、GSH活性以及Sirt1、Nrf2、HO-1、ACSL4、GPX4表达水平。结果与假手术组比较,模型组湿/干重比值、肺组织损伤评分、ACSL4表达水平、Fe^(2+)、TNF-α、IL-6和MDA含量、Sirt1、Nrf2、HO-1信使RNA及蛋白表达水平显著增高(P<0.01),GPX4表达水平及GSH活性显著下降(P<0.01)。与模型组比较,纳美芬组、纳美芬+EX527组湿/干重比值、肺组织损伤评分、ACSL4表达水平、Fe^(2+)、TNF-α、IL-6和MDA含量显著下降(P<0.01),Nrf2、HO-1信使RNA及蛋白表达水平、GPX4表达水平及GSH活性显著增高(P<0.01);其中纳美芬组Sirt1信使RNA及蛋白表达水平显著增高(P<0.01)而纳美芬+EX527组无显著变化(P>0.05)。纳美芬+ML385组湿/干重比值、肺组织损伤评分、TNF-α、IL-6含量显著下降(P<0.01),Sirt1信使RNA及蛋白表达水平显著增高(P<0.01),Nrf2、HO-1信使RNA及蛋白表达水平、ACSL4和GPX4表达水平、Fe^(2+)、MDA含量和GSH活性无显著变化(P>0.05)。纳美芬+Fe-柠檬酸盐组湿/干重比值、肺组织损伤评分、TNF-α、IL-6、MDA含量显著下降(P<0.01);Sirt1、Nrf2、HO-1信使RNA及蛋白表达水平、GSH活性显著增高(P<0.01);Fe^(2+)含量、ACSL4和GPX4表达水平无显著变化(P>0.05)。与纳美芬组比较,纳美芬+EX527组、纳美芬+ML385组、纳美芬+Fe-柠檬酸盐组湿/干重比值、肺组织损伤评分、ACSL4表达水平、Fe^(2+)、TNF-α、IL-6和MDA含量显著增高(P<0.01)、GPX4表达水平及GSH活性显著下降(P<0.01);纳美芬+EX527组Sirt1、Nrf2、HO-1信使RNA及蛋白表达水平显著下降(P<0.01);纳美芬+ML385组Nrf2、HO-1信使RNA及蛋白表达水平显著下降(P<0.01),Sirt1信使RNA及蛋白表达水平无显著变化(P>0.05);纳美芬+Fe-柠檬酸盐组Sirt1、Nrf2、HO-1信使RNA及蛋白表达水平无显著变化(P>0.05)。结论盐酸纳美芬缺血后处理可通过激活Sirt1/Nrf2/HO-1轴抑制铁死亡途径减轻肺缺血-再灌注损伤。