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目的研究4-羟基-2,2,6,6-四甲基哌啶基-N-氧化物(tempol)对高原缺氧小鼠心肌组织的保护作用及机制。方法将110只小鼠随机分为正常对照组、缺氧模型组、乙酰唑胺组和tempol组,单次腹腔注射给药30 min后,在模拟海拔8 000 m环境停留12 h,眼眶取血后,测定血清中乳酸脱氢酶(LDH)和肌酸激酶(CK)活性,然后处死小鼠,检测心肌组织中过氧化氢(H_2O_2)和丙二醛(MDA)含量以及ATP酶和抗氧化酶的活性,蛋白印迹法检测缺氧诱导因子-1α(HIF-1α)、血管内皮生长因子(VEGF)、核因子E2相关因子2(Nrf2)和血红素氧合酶-1(HO-1)蛋白的表达水平。结果与正常对照组相比,缺氧模型组血清中CK和LDH的活性显著增加,心肌组织中H_2O_2和MDA含量显著升高,ATP酶和抗氧化酶的活性显著降低,HIF-1α、VEGF、Nrf2和HO-1蛋白表达增强。经tempol预处理后能够显著降低高原缺氧小鼠血清中CK和LDH的活性,减少心肌组织中H_2O_2和MDA含量,提高ATP酶和抗氧化酶的活性,降低HIF-1α、VEGF蛋白表达,显著提高Nrf2和HO-1蛋白表达。结论 Tempol对高原缺氧诱导的心肌组织损伤具有保护作用,该作用与改善能量代谢,清除自由基,激活Nrf2/HO-1信号途径,提高抗氧化酶活性,降低机体氧化应激有关。
Objective To investigate the protective effect and mechanism of 4-hydroxy-2,2,6,6-tetramethylpiperidinyl-N-oxide (tempol) on myocardium in hypoxia mice. Methods Totally 110 mice were randomly divided into normal control group, hypoxia model group, acetazolamide group and tempol group. After a single intraperitoneal injection for 30 min, they were kept in a simulated altitude of 8 000 m for 12 h, Afterwards, the activity of lactate dehydrogenase (LDH) and creatine kinase (CK) in the serum were determined. Then the mice were sacrificed to detect the content of H 2 O 2 and malondialdehyde (MDA) and the activities of ATPase and antioxidant (HIF-1α), vascular endothelial growth factor (VEGF), nuclear factor E2 (Nrf2) and heme oxygenase-1 (HO-1) were detected by Western blotting. Protein expression levels. Results Compared with the normal control group, the activities of CK and LDH in the serum of hypoxia model group increased significantly, while the content of H 2 O 2 and MDA in myocardium increased significantly, while the activities of ATPase and antioxidant enzymes decreased significantly. The expressions of HIF-1α, VEGF, Nrf2 and HO-1 protein expression increased. After pretreatment with tempol, the activities of CK and LDH in serum of plateau hypoxia mice were significantly decreased, the content of H 2 O 2 and MDA in myocardium was decreased, the activities of ATPase and antioxidant enzymes were increased, and the expressions of HIF-1α and VEGF protein were significantly decreased Improve Nrf2 and HO-1 protein expression. Conclusions Tempol has a protective effect on hypoxia-induced myocardial injury. This effect is related to improving energy metabolism, scavenging free radicals, activating Nrf2 / HO-1 signaling pathway, increasing antioxidant enzyme activity and reducing oxidative stress.