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

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

  • 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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