Li Qi Huo Xue Di Wan alleviates hypoxia-induced injury in human cardiac microvascular endothelial cells by inhibiting apoptosis and necroptosis pathways.

OBJECTIVES: Injury to human cardiac microvascular endothelial cells (HCMECs) compromises myocardial microcirculation and may contribute to major cardiovascular events such as coronary heart disease, posing a serious health threat. Understanding the mechanisms of hypoxia-induced HCMEC damage is thus of great clinical relevance. This study aims to investigate the protective effects and underlying mechanisms of Li Qi Huo Xue Di Wan against hypoxia-induced HCMEC injury. METHODS: HCMECs were cultured under hypoxic conditions for 24 hours to establish a cellular model of hypoxic injury. Cells were divided into six groups: normal control, hypoxia, hypoxia + low-dose Li Qi Huo Xue Di Wan, hypoxia + medium-dose, hypoxia + high-dose, and hypoxia + salvianolic acid B (positive control). Cell viability was assessed using the MTS assay. Lactate dehydrogenase (LDH) release and malondialdehyde (MDA) content were measured to evaluate cytotoxicity and oxidative stress. Activities of superoxide dismutase (SOD), catalase (CAT), caspase-3, and caspase-8 were determined with corresponding assay kits. Apoptosis was analyzed by flow cytometry, and expression of necroptosis-related proteins, receptor-interacting protein kinase 1 (RIPK1) and its phosphorylated form (p-RIPK1), receptor-interacting protein kinase 3 (RIPK3) and its phosphorylated form (p-RIPK3), mixed lineage kinase domain-like protein (MLKL) and its phosphorylated form (p-MLKL), was examined via Western blotting. RESULTS: Compared with the control group, hypoxia significantly decreased cell viability (P<0.01), increased MDA levels (P<0.05), and reduced CAT and SOD activity (P<0.05), accompanied by elevated apoptosis (P<0.01) and increased levels of p-RIPK1, p-RIPK3, and p-MLKL (P<0.05). High-dose Li Qi Huo Xue Di Wan significantly improved cell viability (P<0.01), reduced MDA content (P<0.05), increased CAT activity (P<0.05), and suppressed necroptosis-related protein expression (P<0.05) compared with the hypoxia group. CONCLUSIONS: Li Qi Huo Xue Di Wan exerts a protective effect against hypoxia-induced injury in HCMECs. This effect is mediated by attenuation of oxidative stress, thereby reducing both apoptosis and necroptosis.