RESUMO
BACKGROUND: Ventricular remodeling is the adaptive process in which the heart undergoes changes due to stress, leading to heart failure (HF). The progressive decline in cardiac function is considered to contribute to intestinal barrier impairment. LuQi Formula (LQF) is a traditional Chinese medicine preparation widely used in the treatment of ventricular remodeling and HF. However, the role of LQF in the impairment of intestinal barrier function induced by ventricular remodeling remains unclear. MATERIALS AND METHODS: Ventricular remodeling was induced in rats by permanently ligating the left anterior descending branch coronary artery, and cardiac function indexes were assessed using echocardiography. Heart and colon tissue morphology were observed by hematoxylin-eosin, Masson's trichrome and Alcian Blue Periodic acid Schiff staining. Myocardial cell apoptosis was detected using TUNEL and immunohistochemistry. Circulatory levels of brain natriuretic peptide (BNP), intestinal permeability markers endotoxin, D-lactate and zonulin, as well as inflammatory cytokines tumor necrosis factor alpha and interleukin-1 beta were measured by Enzyme-linked immunosorbent assay. Expression levels of tight junction (TJ) proteins and hypoxia-inducible factor-1 alpha (HIF-1α) in colon tissue were detected by immunofluorescence, immunohistochemistry and western blotting. Cardiac function indexes and intestinal permeability markers of patients with HF were analyzed before and after 2-4 months of LQF treatment. RESULTS: LQF protected cardiac function and alleviated myocardial fibrosis and apoptosis in rats with ventricular remodeling. LQF protected the intestinal barrier integrity in ventricular remodeling rats, including maintaining colonic tissue morphology, preserving the number of goblet cells and normal expression of TJ proteins. Furthermore, LQF upregulated the expression of HIF-1α protein in colon tissue. Intervention with a HIF-1α inhibitor weakened the protective effect of LQF on intestinal barrier integrity. Moreover, a reduction of HIF-1α aggravated ventricular remodeling, which could be alleviated by LQF. Correspondingly, the circulating levels of intestinal permeability markers and BNP in HF patients were significantly decreased, and cardiac function markedly improved following LQF treatment. CONCLUSIONS: We demonstrated that LQF effectively protected cardiac function by preserving intestinal barrier integrity caused by ventricular remodeling, at least partially through upregulating HIF-1α expression.
RESUMO
BACKGROUND: Heart failure (HF) is the terminal stage of all heart diseases that is characterized by irreversible cardiomyocyte injury. Equilibrium of autophagy is essential for cardiac cell survival. The Luhong formula (LHF) has been clinically applied for decades, and has exhibited significant efficacy in improving heart function and alleviating the symptoms of angina pectoris. PURPOSE: To clarify the mechanism of action of LHF and one of its main constituents, hydroxysafflor yellow A (HYSA), in protecting ischemic cardiomyocytes by inhibiting autophagy. METHODS: Cell viability was detected by CCK-8 assay with LHF or HYSA pretreatment followed by hypoxic damage. Immunofluorescence of GFP-LC3-H9C2 and GFP-LC3-HeLa cells was used to observe autophagic flux. Beclin 1 and HIF1α protein expression were assessed using western blotting. LHF was orally administered to Wistar rats following myocardial infarcion. Echocardiography was performed before the rats were sacrificed; immunohistochemistry and western blotting were used to evaluate Beclin 1 and HIF1α expression in the myocardial tissue. Hematoxylin and eosin staining as well as Masson's trichrome staining were used to measure cardiac structure and myocardial fibrosis. RESULTS: LHF and HYSA reversed the hypoxia-induced decrease in cell viability in vitro. LHF and HYSA induced the aggregation of GFP-LC3 puncta and reduced the expression of Beclin 1 protein in H9C2, suggesting that LHF and HYSA may inhibit autophagy activity. Pretreatment with reactive oxygen species (ROS) inducers and inhibitors revealed that LHF and HYSA inhibited autophagy by suppressing cellular ROS. Further studies demonstrated that LHF and HYSA reduced the ROS levels by inhibiting HIF1α. LHF delayed fibrosis and protected heart function in vivo in a rat model of HF following myocardial infarction. Western blotting and immunohistochemistry revealed that LHF effectively reduced the expression of Beclin 1 and HIF1α in the infarcted area of the rat heart. CONCLUSION: These results demonstrate that hydroxysafflor yellow A is the representative bioactive compounent of Luhong Formula on regulating autophagy to protectect cardiomyocytes from hypoxia injury. LHF and HYSA inhibit cardiac autophagy by suppressing HIF1α-mediated ROS production. This study helps to further clarify the underlying mechanism of LHF and provide a scientific basis for its development as a novel cardiovascular therapeutic agent.
