Shenlian extract decreases mitochondrial autophagy to regulate mitochondrial function in microvascular to alleviate coronary artery no‐reflow

Abstract

Shenlian (SL) extract has been proven to be effective in the prevention and treatment of atherosclerosis and myocardial ischemia. However, the function and molecular mechanisms of SL on coronary artery no‐reflow have not been fully elucidated. This study was designed to investigate the contribution of SL extract in repressing excessive mitochondrial autophagy to protect the mitochondrial function and prevent coronary artery no‐reflow. The improvement of SL on coronary artery no‐reflow was observed in vivo experiments and the molecular mechanisms were further explored through vitro experiments. First, a coronary artery no‐reflow rat model was built by ligating the left anterior descending coronary artery for 2 hr of ischemia, followed by 24 hr of reperfusion. Thioflavin S (6%, 1 ml/kg) was injected into the inferior vena cava to mark the no‐reflow area. Transmission electron microscopy was performed to observe the cellular structure, mitochondrial structure, and mitochondrial autophagy of the endothelial cells. Immunofluorescence was used to observe the microvascular barrier function and microvascular inflammation. Cardiac microvascular endothelial cells (CMECs) were isolated from rats. The CMECs were deprived of oxygen–glucose deprivation (OGD) for 2 hr and reoxygenated for 4 hr to mimic the Myocardial ischemia‐reperfusion (MI/R) injury‐induced coronary artery no‐reflow in vitro. Mitochondrial membrane potential was assessed using JC‐1 dye. Intracellular adenosine triphosphate (ATP) levels were determined using an ATP assay kit. The cell total reactive oxygen species (ROS) levels and cell apoptosis rate were analyzed by flow cytometry. Colocalization of mitochondria and lysosomes indirectly indicated mitophagy. The representative ultrastructural morphologies of the autophagosomes and autolysosomes were also observed under transmission electron microscopy. The mitochondrial autophagy‐related proteins (LC3II/I, P62, PINK, and Parkin) were analyzed using Western blot analysis. In vivo, results showed that, compared with the model group, SL could reduce the no‐reflow area from 37.04 ± 9.67% to 18.31 ± 4.01% (1.08 g·kg−1 SL), 13.79 ± 4.77% (2.16 g·kg−1 SL), and 12.67 ± 2.47% (4.32 g·kg−1 SL). The extract also significantly increased the left ventricular ejection fraction (EF) and left ventricular fractional shortening (FS) (p < 0.05 or p < 0.01). The fluorescence intensities of VE‐cadherin, which is a junctional protein that preserves the microvascular barrier function, decreased to ~74.05% of the baseline levels in the no‐reflow rats and increased to 89.87%(1.08 g·kg−1SL), 82.23% (2.16 g·kg−1 SL), and 89.69% (4.32 g·kg−1 SL) of the baseline levels by SL treatment. SL administration repressed the neutrophil migration into the myocardium. The oxygen–glucose deprivation/reoxygenation (OGD/R) model was induced in vitro to mimic microvascular ischemia–reperfusion injury. The impaired mitochondrial function after OGD/R injury led to decreased ATP production, calcium overload, the excessive opening of the Mitochond...

IGF‑1 inhibits palmitic acid‑induced mitochondrial apoptosis in macrophages

“…Previous studies have suggested that excessive mitophagy might result in mitochondrial damage (30)(31)(32). To evaluate whether iGF-1 protect mitochondrial damage based on mitophagy, the present study initially measured the engulfing mitochondria using co-localization of autophagosomes and mitochondria.…”