Tanshinone I inhibits doxorubicin-induced cardiotoxicity by regulating Nrf2 signaling pathway.

BACKGROUND: Doxorubicin (DOX) is a powerful anti-tumor anthracycline drug. However, its clinical use is limited due to the side effect of cardiotoxicity. Tanshinone I (Tan I) is one of the major tanshinones isolated from Salvia miltiorrhiza. Studies have shown that Tan I is effective in the treatment of cardiovascular diseases. However, the potential effects of Tan I against DOX-induced cardiotoxicity (DIC) have yet to be explored. PURPOSE: This study aimed to explore whether Tan I can protect against DIC and to reveal whether Tan I can exert anti-oxidative effect by regulating nuclear erythroid factor 2-related factor 2 (Nrf2) pathway. METHODS: DIC models were established in vivo by intravenous injection of DOX. Echocardiography was used to monitor the cardiac function of mice. Transmission electron microscopy was used to assess mitochondrial damage. Oxidative stress was measured by dihydroethidium (DHE) staining and western blotting. The accumulation and nuclear translocation of Nrf2 was detected by immunofluorescence. H9C2 cellular DIC model was established in vitro to explore the pharmacological mechanism. Nrf2 small interfering (si)-RNA was applied to H9C2 cells to explore whether Tan I exerted protective effect against DIC through Nrf2 signaling pathway. The protective effects of Tan I on mitochondrial function and mitochondrial membrane permeability were measured by MitoSOX™ Red and JC-1 staining assays, respectively. RESULTS: In vivo experiments revealed that Tan I could improve cardiac function and protect against DOX-induced myocardial structural damages in mice models. The oxidative stress induced by DOX was suppressed and apoptosis was mitigated by Tan I treatment. Tan I protected against DOX-induced mitochondrial structural damage. Meanwhile, key proteins in Nrf2 pathways were upregulated by Tan I treatment. In vitro studies showed that Tan I attenuated DOX-induced generation of reactive oxygen species (ROS) in cultured H9C2 cells, reduced apoptotic rates, protected mitochondrial functions and up-regulated Nrf2 signaling pathway. Tan I promoted accumulation and nuclear translocation of Nrf2 protein. In addition, interference of Nrf2 abrogated the anti-oxidative effects of Tan I and reversed the expressions of key proteins in Nrf2 pathway. The protective effects of Tan I on mitochondrial integrity was also mitigated by Nrf2 interference. CONCLUSION: Tan I could reduce oxidative stress and protect against DIC through regulating Nrf2 signaling pathway. Nrf2 is a potential target and Tan I is a novel candidate agent for the treatment of DIC.

Notoginsenoside R1 Ameliorates Cardiac Lipotoxicity Through AMPK Signaling Pathway.

Aims: Cardiac lipotoxicity is the common consequence of lipid metabolism disorders in cardiomyocytes during development of heart failure (HF). Adenosine 5'monophosphate-activated protein kinase (AMPK) acts as an energy sensor and has a beneficial effect in reducing lipotoxicity. Notoginsenoside R1 (NGR1) is extracted from the traditional Chinese medicine Panax notoginseng (Burkill) F.H.Chen (P. notoginseng) and has definite cardioprotective effects. However, whether NGR1 can attenuate HF by mitigating lipotoxicity has not been elucidated yet. This study aimed to explore whether NGR1 plays a protective role against HF by ameliorating cardiac lipotoxicity via the AMPK pathway. Methods: In this study, HF mice model was established by left anterior descending (LAD) ligation. palmitic acid (PA) stimulated H9C2 cell model was applied to clarify the effects and potential mechanism of NGR1 on lipotoxicity. In vivo, NGR1 (7.14 mg/kg/days) and positive drug (simvastatin: 2.9 mg/kg/days) were orally administered for 14 days. Echocardiography was applied to assess heart functions. Lipid levels were measured by Enzyme-linked immunosorbent assay (ELISA) and key proteins in the AMPK pathway were detected by western blots. In vitro, NGR1 (40 µmol/L) or Compound C (an inhibitor of AMPK, 10 µmol/L) was co-cultured with PA stimulation for 24 h in H9C2 cells. CCK-8 assay was used to detect cell viability. Key lipotoxicity-related proteins were detected by western blots and the LipidTOX™ neutral lipid stains were used to assess lipid accumulation. In addition, Apoptosis was assessed by Hoechst/PI staining. Results: NGR1 could significantly improve the cardiac function and myocardial injury in mice with HF and up-regulate the expression of p-AMPK. Impressively, NGR1 inhibited the synthesis of diacylglycerol (DAG) and ceramide and promoted fatty acid oxidation (FAO) in vivo. Moreover, NGR1 significantly promoted expression of CPT-1A, the key enzyme in FAO pathway, and down-regulated the expression of GPAT and SPT, which were the key enzymes catalyzing production of DAG and ceramide. In vitro experiments showed that NGR1 could significantly attenuate lipid accumulation in PA-induced H9C2 cells and the Hoechst/PI staining results showed that NGR1 ameliorated lipotoxicity-induced apoptosis in PA-stimulated H9C2 cell model. Furthermore, co-treatment with inhibitor of AMPK abrogated the protective effects of NGR1. The regulative effects of NGR1 on lipid metabolism were also reversed by AMPK inhibitor. Conclusion: NGR1 could significantly improve the heart function of mice with HF and reduce cardiac lipotoxicity. The cardio-protective effects of NGR1 are mediated by the activation of AMPK pathway.

Qishen granule (QSG) exerts cardioprotective effects by inhibiting NLRP3 inflammasome and pyroptosis in myocardial infarction rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Qishen granule (QSG) is a traditional Chinese medicine formulation that is widely used in clinical practice for the treatment of myocardial infarction (MI), and its efficacy and safety have been well approved. However, the underlying mechanism by which QSG alleviates inflammation and cell pyroptosis remains unknown. AIM OF THE STUDY: The aim of this study was to clarify whether QSG ameliorated MI by inhibiting inflammasome activation and cell pyroptosis. MATERIALS AND METHODS: In vivo, SD male rats were subjected to the left anterior ascending branch (LAD) ligation to construct MI model. And in vitro, OGD/R, ISO, Ang II and LPS-ATP were used to induce H9C2 cell injury. Cell viability and ROS were detected by CCK8 and DCFH-DA dye respectively. Western blots were applied to detect the expression of inflammasome-related proteins. Cell pyroptosis was evaluated by Calcein-AM/PI staining, Hoechst/PI staining and NT-GSDMD expression. RESULTS: QSG administration improved the cardiac function, as well as reduced inflammatory cell infiltration and collagen deposition. In H9C2 cells, OGD/R failed to induce inflammasome activation, while ISO, Ang II and LPS-ATP successfully induced inflammasome activation and cell pyroptosis, as evidenced by increased Caspase-1(P20) and NT-GSDMD. In LPS-ATP induced H9C2 model, ROS production and cell pyroptosis were suppressed when treated with QSG. Furthermore, QSG significantly decreased the protein levels of P65-NF-κB, NLRP3, ASC, Caspase-1 (P20), Cleaved IL-18, Cleaved IL-1ß and NT-GSDMD. CONCLUSION: This study is the first to demonstrate that QSG has cardioprotective effects by inhibiting inflammasome activation and pyroptosis, which are considered as promising therapeutic targets for MI.