Effect of Paclitaxel+Hirudin on the TLR4-MyD88 Signaling Pathway During Inflammatory Activation of Human Coronary Artery Smooth Muscle Cells and Mechanistic Analysis

Background/Aims: Approximately 10%-20% of patients with acute cardiovascular disease who have received coronary intervention suffer restenosis and high inflammation. The stent compound paclitaxel+hirudin was prepared for the treatment of post-intervention restenosis. This study aimed to explore the anti-inflammatory and anti-restenosis mechanisms of paclitaxel+hirudin with regard to the TLR4/MyD88/NF-κB pathway. Methods: Human coronary artery smooth muscle cells (HCASMCs) at 4-6 generations after in vitro culture were used as a model. Lipopolysaccharide (LPS) was used as an inducer to maximally activate the TLR4/MyD88/NF-κB inflammation pathway. After MyD88 knockdown and selective blocking of MyD88 degradation with epoxomicin, the effects of paclitaxel+hirudin stenting on key sites of the TLR4/MyD88/NF-κB pathway were detected using ELISA, Q-PCR, and western blot analysis. Results: LPS at 1 μg/mL for 48 h was the optimal modeling condition for inflammatory activation of HCASMCs. Paclitaxel+hirudin inhibited the levels of key proteins and the gene expression, except for that of the MyD88 gene, of the TLR4-MyD88 pathway. The trend of the effect of paclitaxel+hirudin on the pathway proteins was similar to that of MyD88 knockdown. After epoxomicin intervention, the inhibitory effects of paclitaxel+hirudin on the key genes and proteins of the TLR4-MyD88 pathway were significantly weakened, which even reached pre-intervention levels. Paclitaxel+hirudin affected the MyD88 protein in a dosage-dependent manner. Conclusion: The paclitaxel+hirudin compound promotes MyD88 degradation in the TLR4/MyD88/NF-κB pathway to reduce the activity of TLR4 and NF-κB p65 and to weaken the LPS-initiated inflammatory reactions of IL-1β, IL-6, and TNF-α.