南方医科大学学报

南方医科大学学报 ›› 2022, Vol. 42 ›› Issue (5): 752-759.doi: 10.12122/j.issn.1673-4254.2022.05.18

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褐藻素通过调控Nrf2/Keap1通路缓解糖尿病大鼠心肌肥大

郑冬晓，陈琳琳，韦其慧，朱梓然，刘子略，金 琳，杨观玉，谢 曦   

  1. 海南大学药学院，海南 海口 570228
  • 出版日期:2022-05-20 发布日期:2022-06-02

Fucoxanthin regulates Nrf2/Keap1 signaling to alleviate myocardial hypertrophy in diabetic rats

ZHENG Dongxiao, CHEN Linlin, WEI Qihui, ZHU Ziran, LIU Zilue, JIN Lin, YANG Guanyu, XIE Xi   

  1. School of Pharmaceutical Sciences, Hainan University, Haikou 570228, China
  • Online:2022-05-20 Published:2022-06-02

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摘要： 目的 探索褐藻素（FX）对糖尿病心肌病的保护效应和作用机制。方法 腹腔注射链脲佐菌素建立糖尿病大鼠模型，进行分组：糖尿病组（DM）、褐藻素干预糖尿病组（DM+FX）和二甲双胍干预糖尿病组（DM+Met），另取正常大鼠给予正常喂养作为正常组（Con）。造模成功后连续12周每日灌胃给药，褐藻素组每日给予200 mg/kg褐藻素灌胃，二甲双胍组每日给予230 mg/kg灌胃，糖尿病组同步灌胃生理盐水。HE染色观察各组大鼠心脏细胞肥大情况；Western blot法检测大鼠心脏中纤维化蛋白TGF-β1和FN蛋白表达水平。H9C2细胞分为3组：正常糖组（NG，5.5 mmol/L葡萄糖）、高糖组（HG，45 mmol/L葡萄糖）和褐藻素干预高糖组（HG+1 μmol/L FX）。FITC标记的鬼笔环肽检测大鼠心肌细胞H9C2表面积变化；qRT-PCR法测定各组细胞肥大因子ANP、BNP和β-MHC基因表达变化；Western blot法检测各组大鼠心脏组织和H9C2细胞中Nrf2、Keap1、HO-1、SOD1蛋白表达水平；DCFH-DA探针检测细胞内活性氧水平变化。结果 褐藻素改善糖尿病大鼠心肌纤维化和心肌细胞肥大，同时上调心脏组织中Nrf2和HO-1蛋白表达，抑制Keap1蛋白表达（P<0.05）。褐藻素可抑制高糖诱导H9C2心肌细胞表面积增加，降低ANP、BNP和β-MHC的mRNA表达水平（P<0.05）。褐藻素可促进高糖诱导的H9C2细胞中Nrf2入核，上调下游靶蛋白SOD1和HO-1蛋白表达（P<0.05）来增强细胞抗氧化能力，降低细胞内活性氧的水平。结论 褐藻素具有良好的抗糖尿病心肌纤维化和心肌细胞肥大作用，同时上调Nrf2信号通路并促进下游抗氧化蛋白SOD1和HO-1的表达，降低活性氧水平。

关键词: 褐藻素；糖尿病心肌病；Nrf2/Keap1；氧化应激

Abstract: Objective To investigate the protective effect of fucoxanthin (FX) against diabetic cardiomyopathy and explore the underlying mechanism. Methods Rat models of diabetes mellitus (DM) induced by intraperitoneal injection of streptozotocin (60 mg/kg) were randomized into DM model group, fucoxanthin treatment (DM+FX) group and metformin treatment (DM+Met) group, and normal rats with normal feeding served as the control group. In the two treatment groups, fucoxanthin and metformin were administered after modeling by gavage at the daily dose of 200 mg/kg and 230 mg/kg, respectively for 12 weeks, and the rats in the DM model group were given saline only. HE staining was used to examine the area of cardiac myocyte hypertrophy in each group. The expression levels of fibrotic proteins TGF-β1 and FN proteins in rat hearts were detected with Western blotting. In the cell experiment, the effect of 1 μmol/L FX on H9C2 cell hypertrophy induced by exposure to high glucose (HG, 45 mmol/L) was evaluated using FITC-labeled phalloidin. The mRNA expression levels of the hypertrophic factors ANP, BNP and β-MHC in H9C2 cells were detected using qRT-PCR. The protein expressions of Nrf2, Keap1, HO-1 and SOD1 proteins in rat heart tissues and H9C2 cells were determined using Western blotting. The DCFH-DA probe was used to detect the intracellular production of reactive oxygen species (ROS). Results In the diabetic rats, fucoxanthin treatment obviously alleviated cardiomyocyte hypertrophy and myocardial fibrosis, increased the protein expressions of Nrf2 and HO-1, and decreased the protein expressions of Keap1 in the heart tissue (P<0.05). In H9C2 cells with HG exposure, fucoxanthin significantly inhibited the enlargement of cell surface area, lowered the mRNA expression levels of ANP, BNP and β-MHC (P<0.05), promoted Nrf2 translocation from the cytoplasm to the nucleus, and up-regulated the protein expressions its downstream targets SOD1 and HO-1 (P<0.05) to enhance cellular antioxidant capacity and reduce intracellular ROS production. Conclusion Fucoxanthin possesses strong inhibitory activities against diabetic cardiomyocyte hypertrophy and myocardial fibrosis and is capable of up-regulating Nrf2 signaling to promote the expression of its downstream antioxidant proteins SOD1 and HO-1 to reduce the level of ROS.

Key words: fucoxanthin; diabetic cardiomyopathy; Nrf2/Keap1; oxidative stress