ORIGINAL ARTICLES
CHANG Jinjin, YUE Yanfeng, ZHAO Zhuo
OBJECTIVE To investigate the regulatory effects of salvianolic acid C (SAC) on the level of cuproptosis and inflammatory injury in cardiomyocytes after myocardial infarction (MI). METHODS ① C57BL/6 mice were divided into a sham group, an MI model group, and SAC (5, 10 and 20 mg·kg-1) groups, with 10 mice in each group. Mice in the SAC groups were pretreated with oral gavage of SAC for 1 week, while those in the sham and model groups received an equal volume of saline. One week later, an MI model was established in the model and SAC groups by ligating the left anterior descending coronary artery, while the sham group underwent thoracotomy without ligation. MI size was assessed using triphenyltetrazolium chloride (TTC) staining. Cardiomyocyte apoptosis was evaluated by TUNEL staining. The ultrastructure of cardiomyocyte mitochondria was observed under a transmission electron microscope. ② Mouse cardiomyocytes HL-1 were divided into a control group, an oxygen-glucose deprivation (OGD) model group, OGD+SAC 1, 5 and 10 μmol·L-1 groups, and a OGD+SAC (5 μmol·L-1)+nuclear factor erythroid 2-related factor 2 (Nrf2) inhibitor ML385 (2 μmol·L-1) group. Cells in the OGD+SAC groups were pretreated with SAC for 24 h while those in the OGD+SAC+ML385 group were pretreated with both SAC 5 μmol·L-1 and ML385 2 μmol·L-1 for 24 h. Except for the control group, an OGD model was established in HL-1 cells. ELISA was used to detect the levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and IL-1β in mouse serum and HL-1 cell culture supernatants. The Cu+ detection kit was used to measure Cu+ levels in myocardial tissue and HL-1 cells. Cell viability was assessed using the CCK-8 kit. Apoptosis rates of HL-1 cells were detected by flow cytometry. Reactive oxygen species (ROS) levels in HL-1 cells were measured using a ROS detection kit. Western blotting analysis was performed to detect the expression levels of Nrf2, heme oxygenase-1 (HO-1), and cuproptosis markers, ferredoxin 1 (FDX1) and solute carrier family 31 member 1 (SLC31A1) in myocardial tissue and HL-1 cells. RESLUTS ① Compared with the sham group, the MI model group exhibited increased myocardial infarction size, elevated cardiomyocyte apoptosis rates, mitochondrial swelling, vacuolation, and cristae rupture in cardiomyocytes, increased serum levels of TNF-α, IL-6, and IL-1β, elevated Cu+ levels and expressions of FDX1 and SLC31A1 in myocardial tissue, and decreased expressions of Nrf2 and HO-1 (P<0.01). Compared with the model group, the SAC 5, 10 and 20 mg·kg-1 groups showed
reduced MI size, decreased cardiomyocyte apoptosis rates, alleviated mitochondrial swelling, vacuolation, and cristae rupture, lower serum levels of TNF-α, IL-6 and IL-1β, decreased Cu+ levels and expressions of FDX1 and SLC31A1 in myocardial tissue, and increased expressions of Nrf2 and HO-1 (P<0.05, P<0.01). ② Compared with the cell control group, the OGD model group demonstrated significantly decreased HL-1 cell viability, increased cell apoptosis rates, Cu+ and ROS levels, expressions of FDX1 and SLC31A1, elevated levels of TNF-α, IL-6 and IL-1β in cell culture supernatants, and
decreased expressions of Nrf2 and HO-1 (P<0.01). Compared with the OGD model group, the SAC 1, 5 and 10 μmol·L-1 groups showed increased HL-1 cell viability, decreased cell apoptosis rates, Cu+ and ROS levels, expressions of FDX1 and SLC31A1, reduced levels of TNF-α, IL-6 and IL-1β in cell culture supernatants, and increased expressions of Nrf2 and HO-1 (P<0.05, P<0.01). Compared with the SAC 5 μmol·L-1 group, the SAC 5 μmol·L-1+ML385 2 μmol·L-1 group exhibited decreased cell viability, increased cell apoptosis rates, Cu+ and ROS levels, expressions of FDX1 and SLC31A1, elevated
levels of TNF-α, IL-6, and IL-1β in cell culture supernatants, and decreased expressions of Nrf2 and HO-1 (P<0.01). CONSLUSION SAC can activate the Nrf2/HO-1 signaling pathway, alleviate cuproptosis in cardiomyocytes after MI, and reduces inflammatory damage.
