ObjectiveTo discuss the effect of Nrf2/HO-1 up-regulation on improving anoxia/reoxygenation-induced injury in murine cardiomyocytes and its related mechanism.
MethodsThe primary murine cardiomyocytes were divided into normal culture treatment and anoxia/reoxygenation treatment, and the anoxia/reoxygenation treated cardiomyocytes were divided into model group, Nrf2 overexpression group, HO-1 overexpression group, HO-1 silence+Nrf2 overexpression group.Cell viability was detected by MTT assay, apoptosis was analyzed by TUNEL staining, cardiac troponin Ⅰ(cTnⅠ) and creatine kinase isoenzyme MB(CK-MB) contents in cell culture supernatant were determined by ELISA, and levels of endoplasmic reticulum stress-related molecules were measured by fluorescence quantitative PCR.
ResultsAfter anoxia/reoxygenation treatment, the activity decreased, apoptosis increased, and the contents of cTnⅠ and CK-MB in cell culture supernatant of murine cardiomyocytes increased(P < 0.05).Overexpression of Nrf2 or HO-1 could effectively alleviate anoxia/reoxygenation-induced injury in murine cardiomyocytes(P < 0.05).After pretreatment with HO-1 gene silencing, the protection effect of Nrf2 overexpression was significantly weakened(P < 0.05).In addition, after anoxia/reoxygenation treatment, the mRNA expressions of GRP78, ATF6, CHOP and Caspase-3 in cardiomyocytes increased(P < 0.05).Overexpression of Nrf2 or HO-1 resulted in down-regulation of the expression levels of GRP78, ATF6, CHOP and Caspase-3(P < 0.05), while down-regulation of HO-1 level reduced the inhibitory effect of Nrf2 overexpression on endoplasmic reticulum stress signal transduction(P < 0.05).
ConclusionsThe up-regulation of Nrf2/HO-1 pathway can effectively improve anoxia/reoxygenation-induced injury in cardiomyocytes, which may be related to the suppression of endoplasmic reticulum stress and its downstream apoptosis signaling transduction.
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