Tanshinone IIA protects against chronic intermittent hypoxia-induced myocardial injury via activating the endothelin 1 pathway

Tanshinone IIA inhibited intermittent hypoxia induced neuronal injury through promoting autophagy via AMPK-mTOR signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Chronic intermittent hypoxia (CIH) is the primary pathophysiological process of obstructive sleep apnea (OSA) and is closely linked to neurocognitive dysfunction. Tanshinone IIA (Tan IIA) is extracted from Salvia miltiorrhiza Bunge and used in Traditional Chinese Medicine (TCM) to improve cognitive impairment. Studies have shown that Tan IIA has anti-inflammatory, anti-oxidant, and anti-apoptotic properties and provides protection in intermittent hypoxia (IH) conditions. However, the specific mechanism is still unclear.

AIM OF THE STUDY

To assess the protective effect and mechanism of Tan IIA treatment on neuronal injury in HT22 cells exposed to IH.

MATERIALS AND METHODS

The study established an HT22 cell model exposed to IH (0.1% O₂ 3 min/21% O₂ 7 min for six cycles/h). Cell viability was determined using the Cell Counting Kit-8, and cell injury was determined using the LDH release assay. Mitochondrial damage and cell apoptosis were observed using the Mitochondrial Membrane Potential and Apoptosis Detection Kit. Oxidative stress was assessed using DCFH-DA staining and flow cytometry. The level of autophagy was assessed using the Cell Autophagy Staining Test Kit and transmission electron microscopy (TEM). Western blot was used to detect the expressions of the AMPK-mTOR pathway, LC3, P62, Beclin-1, Nrf2, HO-1, SOD2, NOX2, Bcl-2/Bax, and caspase-3.

RESULTS

The study showed that Tan IIA significantly improved HT22 cell viability under IH conditions. Tan IIA treatment improved mitochondrial membrane potential, decreased cell apoptosis, inhibited oxidative stress, and increased autophagy levels in HT22 cells under IH conditions. Furthermore, Tan IIA increased AMPK phosphorylation and LC3II/I, Beclin-1, Nrf2, HO-1, SOD2, and Bcl-2/Bax expressions, while decreasing mTOR phosphorylation and NOX2 and cleaved caspase-3/caspase-3 expressions.

CONCLUSION

The study suggested that Tan IIA significantly ameliorated neuronal injury in HT22 cells exposed to IH. The neuroprotective mechanism of Tan IIA may mainly be related to inhibiting oxidative stress and neuronal apoptosis by activating the AMPK/mTOR autophagy pathway under IH conditions.

Targeting Oxidative Stress and Endothelial Dysfunction Using Tanshinone IIA for the Treatment of Tissue Inflammation and Fibrosis

Salvia miltiorrhiza Burge (Danshen), a member of the Lamiaceae family, has been used in traditional Chinese medicine for many centuries as a valuable medicinal herb with antioxidative, anti-inflammatory, and antifibrotic potential. Several evidence-based reports have suggested that Salvia miltiorrhiza and its components prevent vascular diseases, including myocardial infarction, myocardial ischemia/reperfusion injury, arrhythmia, cardiac hypertrophy, and cardiac fibrosis. Tanshinone IIA (TanIIA), a lipophilic component of Salvia miltiorrhiza, has gained attention because of its possible preventive and curative activity against cardiovascular disorders. TanIIA, which possesses antioxidative, anti-inflammatory, and antifibrotic properties, could be a key component in the therapeutic potential of Salvia miltiorrhiza. Vascular diseases are often initiated by endothelial dysfunction, which is accompanied by vascular inflammation and fibrosis. In this review, we summarize how TanIIA suppresses tissue inflammation and fibrosis through signaling pathways such as PI3K/Akt/mTOR/eNOS, TGF-β1/Smad2/3, NF-κB, JNK/SAPK (stress-activated protein kinase)/MAPK, and ERK/Nrf2 pathways. In brief, this review illustrates the therapeutic value of TanIIA in the alleviation of oxidative stress, inflammation, and fibrosis, which are critical components of cardiovascular disorders.

The effect of adaptation to hypoxia on cardiac tolerance to ischemia/reperfusion

The acute myocardial infarction (AMI) and sudden cardiac death (SCD), both associated with acute cardiac ischemia, are one of the leading causes of adult death in economically developed countries. The development of new approaches for the treatment and prevention of AMI and SCD remains the highest priority for medicine. A study on the cardiovascular effects of chronic hypoxia (CH) may contribute to the development of these methods. Chronic hypoxia exerts both positive and adverse effects. The positive effects are the infarct-reducing, vasoprotective, and antiarrhythmic effects, which can lead to the improvement of cardiac contractility in reperfusion. The adverse effects are pulmonary hypertension and right ventricular hypertrophy. This review presents a comprehensive overview of how CH enhances cardiac tolerance to ischemia/reperfusion. It is an in-depth analysis of the published data on the underlying mechanisms, which can lead to future development of the cardioprotective effect of CH. A better understanding of the CH-activated protective signaling pathways may contribute to new therapeutic approaches in an increase of cardiac tolerance to ischemia/reperfusion.

Astragaloside IV attenuates chronic intermittent hypoxia-induced myocardial injury by modulating Ca2+ homeostasis

Obstructive sleep apnea syndrome (OSAS) is an important consequence of chronic intermittent hypoxia (CIH). Astragaloside IV (AS-IV) exerts multiple protective effects in diverse diseases. However, whether AS-IV can attenuate CIH-induced myocardial injury is unclear. In this study, rats exposed to CIH were established and treated with AS-IV for 4 weeks. In vitro, H9C2 cardiomyocytes subjected to CIH exposure were treated with AS-IV for 48 hours. Then the cardiac function, morphology, fibrosis, apoptosis and Ca²⁺ homeostasis were determined to assess cardiac damage. Results showed that AS-IV attenuated cardiac dysfunction and histological lesions in CIH rats. The increased TUNEL-positive cells and activated apoptotic proteins in CIH rats were reduced by AS-IV. We also noticed that AS-IV reversed the accumulation of Ca²⁺ and altered expressions of Ca²⁺ handling proteins (decreases of SERCA2a and RYR2, and increases of p-CaMKII and NCX1) under CIH exposure. Furthermore, CIH-induced reduction of SERCA2a activity was increased by AS-IV in rats. Similar results were also observed in H9C2 cells. Altogether, these findings indicate that AS-IV modulates Ca²⁺ homeostasis to inhibit apoptosis, protecting against CIH-induced myocardial injury eventually, suggesting it may be a potential agent for cardiac damage of OSAS patients. SIGNIFICANCE OF THE STUDY: Chronic intermittent hypoxia (CIH) is a great contributor of OSAS, which is closely associated with cardiovascular diseases. It is necessary for developing a promising drug to attenuate CIH-induced myocardial injury. This work suggests that AS-IV can attenuate myocardial apoptosis and calcium disruption, thus protecting against CIH-induced myocardial injury. It may represent a novel therapeutic for cardiac damage of OSAS.

Comprehensive characterization and quantification of multiple components in Dan-Huang-Qu-Yu capsule using a multivariate data processing approach based on microwave-assisted extraction with UHPLC and Q Exactive quadrupole-orbitrap high-resolution mass spectrometry

Dan-Huang-Qu-Yu capsule, a Chinese herbal medicine compound preparation, is widely used for chronic pelvic inflammatory disease. In this study, a rapid, selective, and sensitive microwave-assisted extraction ultra-high-performance liquid chromatography-Q Exactive quadrupole-orbitrap high-resolution mass spectrometry method was developed for analyzing its chemical compositions. A total of 85 compounds, including 22 flavonoids, 8 terpenoids, 5 quinones, 5 phthaleolactone, 23 organic acids, and 22 other compounds were identified from Dan-Huang-Qu-Yu capsule. Among them, 35 major compounds were unambiguously detected by comparing them with reference standards and selected as quality control markers, which were simultaneously determined in Dan-Huang-Qu-Yu capsule. The established method was successfully validated and applied for simultaneous determination of 35 bioactive compounds in Dan-Huang-Qu-Yu capsule from ten sample batches. The quantitative data of the analytes were analyzed by principal component analysis for quality assessment of Dan-Huang-Qu-Yu capsule. Six compounds (e.g., astragaloside IV, salvianolic acid B, ellagic acid, chlorogenic acid, N-butylidenephthalide, and luteolin) were screened out and regarded as chemical markers for quality control of Dan-Huang-Qu-Yu capsule. The established method has been proved to be a novel and useful tool for rapid research of Dan-Huang-Qu-Yu capsule. This research will provide reference for the scientific research of traditional Chinese medicines.

Involvement of Endothelin 1 in Remote Preconditioning-Induced Cardioprotection through connexin 43 and Akt/GSK-3β Signaling Pathway

The present study was aimed to explore the role of endothelins in remote preconditioning (RP)-induced myocardial protection in ischemia-reperfusion (IR) injury. RP stimulus was given by subjecting hind limb to four cycles of ischemia and reperfuion (5 minutes each) using blood pressure cuff in male rats. Following RP, hearts were isolated and subjected to 30 minutes of ischemia and 120 minutes of reperfusion on Langendorff apparatus. The extent of myocardial injury was determined by measuring the levels of LDH-1, CK-MB and cardiac troponin T (cTnT) in coronary effluent; caspase-3 activity and Bcl 2 expression in heart (apoptosis); infarct size by triphenyl tetrazolium chloride and contractility parameters including left ventricular developed pressure, dp/dt_max dp/dt_min and heart rate. RP reduced ischemia reperfusion-induced myocardial injury, increased the levels of endothelin 1 (in blood), Akt-P, GSK-3β-P and P-connexin 43 (in hearts). Pretreatment with ET_A receptor antagonist, BQ 123 (1 and 2 mg/kg), ET_B receptor antagonist, BQ 788 (1 and 3 mg/kg) and dual inhibitor of ET_A and ET_B receptor, bonsentan (25 and 50 mg/kg) abolished these effects of RP. However, the effects of bonsentan were more pronounced in comparison to BQ 123 and BQ 788. It is concluded that RP stimulus may release endothelin 1 in the blood, which may activate myocardial ET_A and ET_B receptors to trigger cardioprotection through connexin 43 and Akt/GSK-3β pathway.