Ling-Gui-Qi-Hua formula alleviates left ventricular myocardial fibrosis in rats with heart failure with preserved ejection fraction by blocking the transforming growth factor-β1 /Smads signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE: Ling-Qui-Qi-Hua (LGQH) decoction, composed of Poria cocos (Schw.) Wolf, Cinnamomum cassia (L.) J. Presl, Paeonia veitchii Lynch, and Atractylodes macrocephala Koidz., is a compound formula derived from Ling-Gui-Zhu-Gan decoction recorded in the Treatise on Febrile and Miscellaneous. It has shown cardioprotective effects on patients or rats with heart failure with preserved ejection fraction (HFpEF). Nevertheless, the active ingredients of LGQH and its anti-fibrotic mechanism remain unknown. AIM OF THE STUDY: To determine the active ingredients in LGQH decoction and verify that LGQH decoction may inhibit left ventricular (LV) myocardial fibrosis in HFpEF rats by blocking the transforming growth factor-β1 (TGF-β1)/Smads signaling pathway from the perspective of animal experiments. MATERIALS AND METHODS: First, liquid chromatography-mass spectrometry (LC-MS) technology was used to identify active components in the LGQH decoction. Secondly, a rat model of the metabolic syndrome-associated HFpEF phenotype was established and subsequently received LGQH intervention. The mRNA and protein expression of targets in the TGF-β1/Smads pathway were detected by quantitative real-time polymerase chain reaction and western blot analysis. Finally, molecular docking was conducted to examine the interactions between the active ingredients in the LGQH decoction and key proteins of the TGF-β1/Smads pathways. RESULTS: According to LC-MS analysis, the LGQH decoction contained 13 active ingredients. In animal experiments, LGQH attenuated LV hypertrophy, enlargement, and diastolic function in HEpEF rats. Mechanically, LGQH not only down-regulated TGF-β1, Smad2, Smad3, Smad4, α-SMA, Coll I, and Coll III mRNA expressions and TGF-β1, Smad2, Smad3, P-Smad2/Smad3, Smad4, α-SMA, and Coll I protein expressions, but also up-regulated Smad7 mRNA and protein expressions, which ultimately led to myocardial fibrosis. Furthermore, molecular docking confirmed that 13 active ingredients in the LGQH decoction have excellent binding activities to the critical targets of the TGF-β1/Smads pathway. CONCLUSION: LGQH is a modified herbal formulation with multiple active ingredients. It might alleviate LV remodeling and diastolic dysfunction and inhibit LV myocardial fibrosis by blocking TGF-β1/Smads pathways in HFpEF rats.