时明阳, 胡倩, 毕顶念, 汪红玲, 张爱华, 胡勇. Dicer1、miR-155表达在亚砷酸钠致大鼠肝损伤中的作用[J]. 环境与职业医学, 2021, 38(6): 643-648. DOI: 10.13213/j.cnki.jeom.2021.20569
引用本文: 时明阳, 胡倩, 毕顶念, 汪红玲, 张爱华, 胡勇. Dicer1、miR-155表达在亚砷酸钠致大鼠肝损伤中的作用[J]. 环境与职业医学, 2021, 38(6): 643-648. DOI: 10.13213/j.cnki.jeom.2021.20569
SHI Mingyang, HU Qian, BI Dingnian, WANG Hongling, ZHANG Aihua, HU Yong. Roles of Dicer1 and miR-155 expression in sodium arsenite-induced liver damage in rats[J]. Journal of Environmental and Occupational Medicine, 2021, 38(6): 643-648. DOI: 10.13213/j.cnki.jeom.2021.20569
Citation: SHI Mingyang, HU Qian, BI Dingnian, WANG Hongling, ZHANG Aihua, HU Yong. Roles of Dicer1 and miR-155 expression in sodium arsenite-induced liver damage in rats[J]. Journal of Environmental and Occupational Medicine, 2021, 38(6): 643-648. DOI: 10.13213/j.cnki.jeom.2021.20569

Dicer1、miR-155表达在亚砷酸钠致大鼠肝损伤中的作用

Roles of Dicer1 and miR-155 expression in sodium arsenite-induced liver damage in rats

  • 摘要: 背景

    Dicer1参与微小核糖核酸(miRNA)的剪切,miR-155是一种常见的miRNA,能与靶mRNA 3’非翻译区结合,导致mRNA降解或翻译抑制。

    目的

    探讨Dicer1、miR-155表达在不同浓度亚砷酸钠致大鼠肝损伤中的作用及机制。

    方法

    24只Wistar大鼠适应性喂养1周后,随机分为对照、低/中/高浓度染毒组4组,每组6只,雌雄各半,分别自由饮用0、25、50、100 mg·L-1亚砷酸钠水溶液,正常饮食,持续24周。观察各组大鼠毛发光泽度、活动度,每周同一时间称量动物体重。染砷结束后麻醉解剖大鼠,大体观察肝组织情况。采用HE染色检测肝组织病理,按照试剂盒步骤检测肝匀浆超氧化物歧化酶1(SOD1)、谷胱甘肽过氧化物酶(GSH-Px)活性、丙二醛(MDA)含量,实时荧光定量PCR法检测各组大鼠肝组织Dicer1、miR-155和SOD1转录水平,免疫组化分析各组大鼠肝组织Dicer1和SOD1蛋白表达水平,并采用Pearson相关分析探究各指标间的相关性。

    结果

    随着染砷浓度增加,染毒组大鼠毛发光泽度、活动度降低。与对照组相比,中、高浓度染毒组大鼠体重下降(均P < 0.05);各染毒组大鼠肝砷含量逐渐上升(均P < 0.05);肝组织炎性浸润、空泡变、细胞坏死愈加严重;肝匀浆SOD1、GSH-Px酶活性均逐渐下降,MDA含量上升(均P < 0.05);肝组织Dicer1、miR-155、SOD1 mRNA转录水平均上升(均P < 0.05);肝组织Dicer1蛋白表达上升,SOD1蛋白表达下降(均P < 0.05)。肝组织miR-155表达水平与Dicer1蛋白表达水平呈正相关(r=0.670,P < 0.05),与SOD1蛋白表达水平呈负相关(r=-0.634,P < 0.05)。

    结论

    砷诱导Dicer1基因及蛋白表达增加,可能促进miR-155高表达后与SOD1 3’非翻译区区结合,抑制SOD1翻译,导致SOD1蛋白表达和酶活性下降,进而造成肝脏损伤。

     

    Abstract: Background

    Dicer1 is involved in the cleavage of microribonucleic acid (miRNA). miR-155 is a common miRNA that can bind to the 3'untranslated region of target mRNA, leading to mRNA degradation or translation inhibition.

    Objective

    This experiment explores the roles and mechanisms of Dicer1 and miR-155 expressions in liver injury induced by different concentrations of sodium arsenite in rats.

    Methods

    After adaptive feeding for one week, 24 Wistar rats were randomly divided into 4 groups: control, low-, medium-, and high-dose groups, each group consisting of 6 rats, half male and half female. The rats were freely given drinking water containing 0, 25, 50, and 100 mg·L-1 sodium arsenite and had a normal diet for 24 weeks. The changes of hair gloss and mobility were observed, and all of them were weighed at the same time every week. After arsenic exposure, the rats were anesthetized and dissected, and the pathological changes of liver tissues were observed. The activities of superoxide dismutase 1 (SOD1) and glutathione peroxidase (GSH-Px), and the content of malondialdehyde (MDA) in liver homogenate were detected according to the instructions of the kit. Moreover, the transcriptional expression levels of miR-155, Dicer1, and SOD1 in liver tissues were detected by quantitative real-time PCR (qRT-PCR), and the levels of protein expression of Dicer1 and SOD1 were analyzed by immunohistochemistry. The correlation between above indicators was evaluated by Pearson correlation analysis.

    Results

    With the increase of arsenic exposure dose, the hair gloss and mobility of rats were decreased. Compared with the control group, the weight of the 50 and 100 mg·L-1 arsenic groups were decreased (P < 0.05); the liver arsenic levels were increased in all arsenic groups (P < 0.05); inflammatory infiltration, vacuolation, and cell necrosis of liver tissues were more serious; the activities of SOD1 and GSH-Px in liver homogenate were decreased, while MDA content were increased (all P < 0.05); the transcriptional expression levels of Dicer1, miR-155, and SOD1 in liver tissues were increased gradually (all P < 0.05); the Dicer1 protein expression levels in liver tissues were increased, while the SOD1 protein expression levels were decreased (all P < 0.05). The levels of miR-155 in liver tissues were positively correlated with the protein expression levels of Dicer1 (r=0.670, P < 0.05), but negatively correlated with the protein expression levels of SOD1 (r=-0.634, P < 0.05).

    Conclusion

    Arsenic induces increases of Dicer1 gene and protein expression, which may promote the overexpression of miR-155 to bind to the SOD1 3'UTR region, inhibit SOD1 translation, lead to the decrease of SOD1 protein expression and enzyme activity, and in turn cause liver damage.

     

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