| Summary: | Background: Increasing evidence indicates that myocardial oxidative injury plays a crucial role in the pathophysiology of cardiac hypertrophy (CH) and heart failure (HF). The active component of rhubarb, rhein exerts significant actions on oxidative stress and inflammation. Nonetheless, its role in cardiac remodeling remains unclear. Methods: CH was induced by angiotensin II (Ang II, 1.4 mg/kg/d for 4 weeks) in male C57BL/6 J mice. Then, rhein (50 and 100 mg/kg) was injected intraperitoneally for 28 days. CH, fibrosis, oxidative stress, and cardiac function in the mice were examined. In vitro, neonatal rat cardiomyocytes (CMs) and cardiac fibroblasts (CFs) pre-treated with rhein (5 and 25 μM) were challenged with Ang II. We performed RNA sequencing to determine the mechanistic role of rhein in the heart. Results: Rhein significantly suppressed Ang II-induced CH, fibrosis, and reactive oxygen species production and improved cardiac systolic dysfunction in vivo. In vitro, rhein significantly attenuated Ang II-induced CM hypertrophy and CF collagen expression. In addition, rhein obviously alleviated the increased production of superoxide induced by Ang II. Mechanistically, rhein inhibited FGF23 expression significantly. Furthermore, FGF23 overexpression abolished the protective effects of rhein on CMs, CFs, and cardiac remodeling. Rhein reduced FGF23 expression, mostly through the activation of AMPK (AMP-activated protein kinase). AMPK activity inhibition suppressed Ang II-induced CM hypertrophy and CF phenotypic transformation. Conclusion: Rhein inhibited Ang II-induced CH, fibrosis, and oxidative stress during cardiac remodeling through the AMPK–FGF23 axis. These findings suggested that rhein could serve as a potential therapy in cardiac remodeling and HF. © 2022, The Author(s).
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